fix: move datasource error handling into index (#5662)

lib/datasource/cdnjs/index.spec.ts

lib/datasource/cdnjs/index.ts

lib/datasource/crate/index.spec.ts

lib/datasource/crate/index.ts

lib/datasource/dart/index.spec.ts

lib/datasource/dart/index.ts

lib/datasource/docker/got.spec.ts

lib/datasource/galaxy/index.spec.ts

lib/datasource/galaxy/index.ts

lib/datasource/git-submodules/index.spec.ts

lib/datasource/git-submodules/index.ts

lib/datasource/git-tags/index.spec.ts

lib/datasource/git-tags/index.ts

lib/datasource/github-releases/index.ts

lib/datasource/github-tags/index.ts

lib/datasource/gitlab-tags/__snapshots__/index.spec.ts.snap

lib/datasource/gitlab-tags/index.spec.ts

lib/datasource/gitlab-tags/index.ts

lib/datasource/gradle-version/index.ts

lib/datasource/helm/index.spec.ts