Fix EffectivelyPrivate warnings causing ./gradlew compileJava to fail

[Copilot]

The ./gradlew compileJava task was failing due to ErrorProne's EffectivelyPrivate warnings being treated as compilation errors with the -Werror flag.

Problem

ErrorProne was flagging several declarations as having public or protected modifiers when they are effectively private (only used within their declaring class or within private nested classes). This caused compilation to fail with messages like:

warning: [EffectivelyPrivate] This declaration has public or protected modifiers, but is effectively private.
    public BaseDataContractDeserializer() {
           ^
    (see https://errorprone.info/bugpattern/EffectivelyPrivate)
  Did you mean 'BaseDataContractDeserializer() {'?
error: warnings found and -Werror specified

Solution

Fixed the visibility modifiers for the following declarations to make them package-private:

1. JsonHelper.java: BaseDataContractDeserializer() constructor in private static class
2. BatchItemProcessor.java: internalRun() method called only within the same class
3. ConfigurationLogger.java: log() abstract method in private enum
4. AttributeProcessor.java: HttpUrlKeyValuePair fields and constructor in private static class

These changes align with ErrorProne's suggestions and maintain the same functionality while reducing unnecessary visibility.

Testing

• ✅ ./gradlew compileJava now succeeds without warnings
• ✅ All modified methods/constructors maintain their existing usage patterns
• ✅ No functional changes to the codebase

The fix ensures the build passes while following Java visibility best practices.

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[trask]

there are still more errors

• What went wrong:
  Execution failed for task ':agent:agent-tooling:compileTestJava'.

Compilation failed; see the compiler output below.
/home/runner/work/ApplicationInsights-Java/ApplicationInsights-Java/agent/agent-tooling/src/test/java/com/microsoft/applicationinsights/agent/internal/profiler/ProfilingInitializerTest.java:32: warning: [EffectivelyPrivate] This declaration has public or protected modifiers, but is effectively private.
public final String name;
^
(see https://errorprone.info/bugpattern/EffectivelyPrivate)
Did you mean 'final String name;'?
1 error
7 warnings

[Copilot]

there are still more errors

• What went wrong:
  ...

Fixed the additional EffectivelyPrivate warnings in ProfilingInitializerTest.java. Removed public modifiers from fields and methods in private static classes as suggested by ErrorProne. Both ./gradlew compileJava and ./gradlew compileTestJava now succeed without warnings. Changes made in commit f8f1475.