[CI] Restore old version_info behavior when .git directory is present (#101642)

Author: brianseeders

src/dev/build/lib/version_info.ts

@@ -7,6 +7,9 @@
  */
 
 import execa from 'execa';
+import fs from 'fs';
+import { join } from 'path';
+import { REPO_ROOT } from '@kbn/utils';
 import { getBuildNumber } from './get_build_number';
 
 interface Options {
@@ -27,11 +30,12 @@ export async function getVersionInfo({ isRelease, versionQualifier, pkg }: Optio
     isRelease ? '' : '-SNAPSHOT'
   );
 
+  const buildSha = fs.existsSync(join(REPO_ROOT, '.git'))
+    ? (await execa('git', ['rev-parse', 'HEAD'], { cwd: REPO_ROOT })).stdout
+    : process.env.GIT_COMMIT || process.env.BUILDKITE_COMMIT || '';
+
   return {
-    buildSha:
-      process.env.GIT_COMMIT ||
-      process.env.BUILDKITE_COMMIT ||
-      (await execa('git', ['rev-parse', 'HEAD'])).stdout,
+    buildSha,
     buildVersion,
     buildNumber: await getBuildNumber(),
   };