Address feedback: cache git version, improve error handling, add telemetry

- Cache the git version to avoid recomputing on repeated calls
- Refactor getGitVersion to getGitVersionOrThrow with detailed errors
- Add getGitVersion that logs errors and handles caching
- Add makeTelemetryDiagnostic helper to diagnostics.ts
- Add logGitVersionTelemetry function to log git version telemetry
- Call logGitVersionTelemetry in init-action.ts
- Add resetCachedGitVersion for testing
- Update tests to work with new function signatures and caching

Co-authored-by: henrymercer <14129055+henrymercer@users.noreply.github.com>

src/init-action.ts

@@ -37,6 +37,7 @@ import {
 import { EnvVar } from "./environment";
 import { Feature, Features } from "./feature-flags";
 import { loadPropertiesFromApi } from "./feature-flags/properties";
+import { logGitVersionTelemetry } from "./git-utils";
 import {
   checkInstallPython311,
   checkPacksForOverlayCompatibility,
@@ -433,6 +434,9 @@ async function run() {
       );
     }
 
+    // Log Git version telemetry
+    await logGitVersionTelemetry(config, logger);
+
     // Forward Go flags
     const goFlags = process.env["GOFLAGS"];
     if (goFlags) {