refactor: refactor GitHub actions and API handling

- Remove the conditional checking for `GITHUB_ACTION_PATH` before calling `warnUnsupportedRESTAPIInputs`
- Change in procedure for getting changed files from the REST API.

src/main.ts

@@ -256,9 +256,7 @@ export async function run(): Promise<void> {
     (!hasGitDirectory || inputs.useRestApi)
   ) {
     core.info("Using GitHub's REST API to get changed files")
-    if (process.env.GITHUB_ACTION_PATH) {
-      await warnUnsupportedRESTAPIInputs({inputs})
-    }
+    await warnUnsupportedRESTAPIInputs({inputs})
     await getChangedFilesFromRESTAPI({
       inputs,
       filePatterns,