fix(ci): update Codecov action and remove hardcoded version assertion

[lucarlig]

Codecov action updates fail the catalog test because it asserts an exact action SHA and version comment. Update the coverage upload action to v7.1.1, the latest release, pinned to commit 303a32d7a59b442fa8d48b6a1cc6825c09c847a5, and remove that hardcoded assertion while retaining the surrounding workflow checks.

Supersedes #188.

Validation:

• make plugins-validate passed: 148 tests, with 3 skips for missing Jinja2 and unbuilt PII extensions.
• git diff --check passed.
• Repository pre-commit hooks passed for both changed files, including YAML validation and secret detection.

[msureshkumar88]

Reviewed both changed files. No blocking findings. Verified the pinned commit matches the signed Codecov v7.1.1 tag and the existing coverage upload inputs remain compatible. Removing the exact-version assertion preserves the surrounding coverage and workflow checks. Local validation: make plugins-validate passed (148 tests, 2 skipped); git diff --check passed. GitHub CI is still queued/running at review time.