feat: Cache compacted PR body structure (#15303)

lib/modules/platform/azure/__snapshots__/index.spec.ts.snap

lib/modules/platform/azure/__snapshots__/util.spec.ts.snap

lib/modules/platform/azure/util.ts

...latform/bitbucket-server/__snapshots__/index.spec.ts.snap

lib/modules/platform/bitbucket-server/utils.ts

...dules/platform/bitbucket/__snapshots__/index.spec.ts.snap

lib/modules/platform/bitbucket/utils.ts

lib/modules/platform/gitea/__snapshots__/index.spec.ts.snap

lib/modules/platform/gitea/index.ts

lib/modules/platform/github/__snapshots__/index.spec.ts.snap

lib/modules/platform/github/common.ts

lib/modules/platform/github/index.spec.ts

lib/modules/platform/github/pr.ts

lib/modules/platform/github/types.ts

lib/modules/platform/gitlab/__snapshots__/index.spec.ts.snap

lib/modules/platform/gitlab/index.ts

lib/modules/platform/pr-body.spec.ts

lib/modules/platform/pr-body.ts

lib/modules/platform/types.ts

lib/workers/repository/onboarding/pr/index.spec.ts