Fix Javadoc errors in JFR profiles shim

[thswlsqls]

Description

• Fix the @return tag on JfrLocationDataCompositor.create(...), which said ProfilesDictionaryCompositor but the method returns JfrLocationDataCompositor.
• Fix two typos in the JfrExecutionSampleEventConverter class Javadoc: "steam" -> "stream", "are need" -> "are needed".
• Javadoc-only; no behavior, signature, or public API change.
• Open PR profiles: improve JFR export example #8349 also edits these files but not these Javadoc lines, so there is no collision; happy to fold into profiles: improve JFR export example #8349 if a maintainer prefers.

Testing done

• Docs-only, test-exempt; ./gradlew :opentelemetry-jfr-profiles-shim:check passed (compile, spotlessCheck, ErrorProne/NullAway).
• Module is unpublished, so no japicmp/apidiff and no CHANGELOG entry.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.77%. Comparing base (824334c) to head (0cdae54).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8503   +/-   ##
=========================================
  Coverage     78.77%   78.77%           
  Complexity     8579     8579           
=========================================
  Files          1009     1009           
  Lines         28993    28993           
  Branches       3599     3599           
=========================================
  Hits          22839    22839           
  Misses         5311     5311           
  Partials        843      843           

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