chore: convert fixtures to typescript (#5229)

test/config/config/_fixtures/argv.ts

test/config/config/_fixtures/file-with-repo-presets.js

test/config/config/_fixtures/file.js

test/config/config/_fixtures/file2.js

test/config/config/_fixtures/index.js

test/config/file.spec.ts

test/config/index.spec.ts

test/config/migrate-validate.spec.ts

test/platform/bitbucket-server/_fixtures/responses.ts

test/platform/bitbucket/_fixtures/responses.ts

test/workers/repository/process/fetch.spec.ts

test/workers/repository/process/index.spec.ts