Minor Refactor of ExecutorchRuntimeException (#16193)

- Add dedicated helper function to retreive detailed error logs
- Make ExecutorchInvalidArgumentException extend
ExecutorchRuntimeException

### Summary
[PLEASE REMOVE] See [CONTRIBUTING.md's Pull
Requests](https://github.com/pytorch/executorch/blob/main/CONTRIBUTING.md#pull-requests)
for ExecuTorch PR guidelines.

[PLEASE REMOVE] If this PR closes an issue, please add a `Fixes
#<issue-id>` line.

[PLEASE REMOVE] If this PR introduces a fix or feature that should be
the upcoming release notes, please add a "Release notes: <area>" label.
For a list of available release notes labels, check out
[CONTRIBUTING.md's Pull
Requests](https://github.com/pytorch/executorch/blob/main/CONTRIBUTING.md#pull-requests).

### Test plan
[PLEASE REMOVE] How did you test this PR? Please write down any manual
commands you used and note down tests that you have written if
applicable.

Co-authored-by: Github Executorch <github_executorch@arm.com>

Author: psiddh

extension/android/executorch_android/src/main/java/org/pytorch/executorch/ExecutorchRuntimeException.java

@@ -75,50 +75,32 @@ public class ExecutorchRuntimeException extends RuntimeException {
   }
 
   static class ErrorHelper {
-    private static final boolean ENABLE_READ_LOG_BUFFER_LOGS = true;
-    // Reusable StringBuilder instance
-    private static final StringBuilder sb = new StringBuilder();
-
     static String formatMessage(int errorCode, String details) {
-      synchronized (sb) {
-        sb.setLength(0); // Clear the StringBuilder before use
+      String baseMessage = ERROR_CODE_MESSAGES.get(errorCode);
+      if (baseMessage == null) {
+        baseMessage = "Unknown error code 0x" + Integer.toHexString(errorCode);
+      }
 
-        String baseMessage = ERROR_CODE_MESSAGES.get(errorCode);
-        if (baseMessage == null) {
-          baseMessage = "Unknown error code 0x" + Integer.toHexString(errorCode);
-        }
+      String safeDetails = details != null ? details : "No details provided";
+      return String.format(
+          "[Executorch Error 0x%s] %s: %s",
+          Integer.toHexString(errorCode), baseMessage, safeDetails);
+    }
 
-        sb.append("[Executorch Error 0x")
-            .append(Integer.toHexString(errorCode))
-            .append("] ")
-            .append(baseMessage)
-            .append(": ")
-            .append(details);
-        if (ENABLE_READ_LOG_BUFFER_LOGS) {
-          try {
-            String[] logEntries = Module.readLogBufferStatic(); // JNI call
-            if (logEntries != null && logEntries.length > 0) {
-              sb.append("\n Detailed logs:\n");
-            }
-            formatLogEntries(sb, logEntries);
-          } catch (Exception e) {
-            sb.append("Failed to retrieve detailed logs: ").append(e.getMessage());
+    static String getDetailedErrorLogs() {
+      StringBuilder sb = new StringBuilder();
+      try {
+        String[] logEntries = Module.readLogBufferStatic(); // JNI call
+        if (logEntries != null && logEntries.length > 0) {
+          sb.append("\nDetailed logs:\n");
+          for (String entry : logEntries) {
+            sb.append(entry).append("\n");
           }
         }
-
-        return sb.toString();
-      }
-    }
-
-    // Append log entries to the provided StringBuilder
-    private static void formatLogEntries(StringBuilder sb, String[] logEntries) {
-      if (logEntries == null || logEntries.length == 0) {
-        sb.append("No detailed logs available.");
-        return;
-      }
-      for (String entry : logEntries) {
-        sb.append(entry).append("\n");
+      } catch (Exception e) {
+        sb.append("Failed to retrieve detailed logs: ").append(e.getMessage());
       }
+      return sb.toString();
     }
   }
 
@@ -133,16 +115,14 @@ public int getErrorCode() {
     return errorCode;
   }
 
-  // Idiomatic Java exception for invalid arguments.
-  public static class ExecutorchInvalidArgumentException extends IllegalArgumentException {
-    private final int errorCode = INVALID_ARGUMENT;
+  public String getDetailedError() {
+    return ErrorHelper.getDetailedErrorLogs();
+  }
 
+  // Idiomatic Java exception for invalid arguments - extends ExecutorchRuntimeException
+  public static class ExecutorchInvalidArgumentException extends ExecutorchRuntimeException {
     public ExecutorchInvalidArgumentException(String details) {
-      super(ErrorHelper.formatMessage(INVALID_ARGUMENT, details));
-    }
-
-    public int getErrorCode() {
-      return errorCode;
+      super(INVALID_ARGUMENT, details);
     }
   }