feat: add --no-ping flag to skip health check in inject-secrets (#4342)

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> **Low Risk**
> Low risk: small CLI behavior change gated behind a new flag, with no
changes to secret resolution or output formatting unless `--no-ping` is
used.
>
> **Overview**
> `inject-secrets` now supports a `--no-ping` flag that skips the
startup health check reading `op://global/PING/text`, allowing use with
service-account tokens that can’t access the global vault.
>
> Updates the Azure integration test README to include `--no-ping` in
the manual credential injection example.
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
4d1d7872ab5326be96e6279c35097bdc6989db00. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

GitOrigin-RevId: 176cfdce7974f4441fbdb2e85caab571a4366743

Author: Lionel-Wilson

sources/azure/integration-tests/README.md

@@ -108,6 +108,7 @@ To inject credentials manually (e.g. for debugging), run:
 
 ```bash
 go run build/inject-secrets/main.go \
+  --no-ping \
   --secret-file .github/env/op.azure-cloud-agent.secret \
   --env-file .github/env/op.azure-cloud-agent.env \
   --output-file .env.azure-cloud-agent