Fix trailing whitespace in CHANGELOG.md breaking spotless check

[Copilot]

The common / spotless job failed at :spotlessMiscCheck because the Unreleased section of CHANGELOG.md contained a blank line with trailing whitespace, which violates the trimTrailingWhitespace() rule applied by the misc format in ai.spotless-conventions.

Build output:

> The following files had format violations:
      CHANGELOG.md
          @@ -4,7 +4,7 @@
           *·Add·Java·agent·support·for·ServiceProfiler·targeted·collection·plans·by·cloud·role·or
           ··role-qualified·instance
          -··
          +

Changes

• CHANGELOG.md: adds the Unreleased entry for ServiceProfiler targeted collection plans with the separating blank line truly empty (no trailing spaces), matching what ./gradlew spotlessApply would produce.