refactor(test): delete ConfigDrivenPipelineTest (superseded by unified-pipeline tests)

ConfigDrivenPipelineTest exclusively exercised ProjectConfigLoader.parseProjectConfig(Map)
and .loadProjectConfig(Path) — the deprecated static legacy-POJO parsers being
deleted in the next commit. Every unique assertion has equivalent coverage on
the unified pipeline:

- languages/detectors.categories/detectors.include/exclude/parsers/pipeline map
  parsing: covered by UnifiedConfigLoaderTest (loadsDetectorsCategoriesAndInclude,
  loadsIndexingParsersList, loadsIndexingParallelismAsInteger, fullFileRoundTripsEveryField).
- legacy .osscodeiq.yml end-to-end with flat keys: covered by
  ProjectConfigLoaderApplyOverridesTest (ported in the prior commit).
- empty/missing-file semantics: covered by
  UnifiedConfigLoaderTest.missingFileProducesEmptyOverlay and
  ProjectConfigLoaderApplyOverridesTest.missingConfigFileReturnsEmptyOverlay.
- ProjectConfig.empty() "no filters" assertion: equivalent to
  CodeIqUnifiedConfig.empty() behavior pinned in ConfigDefaultsTest.

No unique coverage lost. Removing the file (not porting) keeps the test tree
clean — parseProjectConfig is a private implementation detail of the legacy
shim, not an API worth separate test coverage after migration.

Full suite: 3288 -> 3277 tests (-11), 0 failures, 31 skipped.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: aksOps