ref: convert sourceMapArtifact.js to typescript (#54984)

fixtures/js-stubs/sourceMapArtifact.js → fixtures/js-stubs/sourceMapArtifact.tsx

@@ -1,4 +1,6 @@
-export function SourceMapArtifact(params = {}) {
+import {Artifact} from 'sentry/types';
+
+export function SourceMapArtifact(params: Partial<Artifact> = {}): Artifact {
   return {
     sha1: '111111111',
     dist: null,