refactor(ci): migrate triggers to standard multiline string format

## Context
In `bcgov/actions`, the `diff-triggers` action has been rewritten in Node.js (v2.0.0). As part of this transition:
1. The new action natively supports the GitHub Actions standard **newline-separated multiline string** format (e.g., using YAML block literal `|`).
2. The old Bash-style parenthesized list format `('backend/' 'frontend/')` has been deprecated and now generates workflow warning notices when used.

Since `quickstart-openshift` is the starter template repository for new applications, it should be updated to use this modern syntax to avoid warnings and set the correct pattern for downstream repositories.

This transition should be scheduled when the template is updated to reference the consolidated `bcgov/actions` repository.

## Proposed Changes

### 1. In `.github/workflows/pr-open.yml`
- Update `builds` job matrix triggers (around line 31):
```yaml
triggers: |
${{ matrix.package }}/
.github/workflows/
```
- Update `deploys` job triggers (around line 43):
```yaml
triggers: |
backend/
frontend/
migrations/
common/
.github/workflows/
```

### 2. In `.github/workflows/analysis.yml`
- Update `backend-tests` job triggers (around line 58):
```yaml
triggers: |
backend/
```
- Update `frontend-tests` job triggers (around line 87):
```yaml
triggers: |
frontend/
```