fix(platform): don’t pass parentBranch to platform commitFilesToBranch (#6227)

lib/platform/azure/index.ts

lib/platform/bitbucket-server/index.ts

lib/platform/bitbucket/index.ts

lib/platform/common.ts

lib/platform/git/storage.spec.ts

lib/platform/git/storage.ts

lib/platform/gitea/index.spec.ts

lib/platform/gitea/index.ts

lib/platform/github/index.ts

lib/platform/gitlab/index.ts

lib/workers/branch/__snapshots__/commit.spec.ts.snap

lib/workers/branch/commit.ts