Fix verbosity log tests to use regex matching

The SciMLLogging package now adds a prefix to log messages
("Verbosity toggle: <option_name> \n ..."), so tests that used
exact string matching for log messages were failing. Changed
the tests to use regex patterns instead, which matches the message
content regardless of any prefix.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ChrisRackauckas

test/verbosity.jl

@@ -101,19 +101,19 @@ end
     prob = LinearProblem(A, b)
 
     @test_logs (:warn,
-        "LU factorization failed, falling back to QR factorization. `A` is potentially rank-deficient.") solve(
+        r"LU factorization failed, falling back to QR factorization\. `A` is potentially rank-deficient\.") solve(
         prob,
         verbose = LinearVerbosity(default_lu_fallback = WarnLevel()))
 
     @test_logs (:info,
-        "LU factorization failed, falling back to QR factorization. `A` is potentially rank-deficient.") solve(
+        r"LU factorization failed, falling back to QR factorization\. `A` is potentially rank-deficient\.") solve(
         prob,
         verbose = LinearVerbosity(default_lu_fallback = InfoLevel()))
 
     verb = LinearVerbosity(default_lu_fallback = WarnLevel())
 
     @test_logs (:warn,
-        "LU factorization failed, falling back to QR factorization. `A` is potentially rank-deficient.") solve(
+        r"LU factorization failed, falling back to QR factorization\. `A` is potentially rank-deficient\.") solve(
         prob,
         verbose = verb)
 end