Use kotlinParserBuilder argument rather than new builder

[timtebeek]

Resolves unused field warning.

Don't think this was intentional; functionally there should be no change as the builders are the same. At most we might see effects of the .clone(), which would be good to surface.

rewrite-maven-plugin/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java

Lines 185 to 186 in ffd2373

	sourceFiles = Stream.concat(sourceFiles, processMainSources(mavenProject, javaParserBuilder.clone(), kotlinParserBuilder.clone(), rp, projectProvenance, alreadyParsed, ctx));
	sourceFiles = Stream.concat(sourceFiles, processTestSources(mavenProject, javaParserBuilder.clone(), kotlinParserBuilder.clone(), rp, projectProvenance, alreadyParsed, ctx));