chore(ci): Remove codecov steps from jobs that produce no coverage/JUnit data (#20244)

## Summary

- Remove `getsentry/codecov-action` from CI jobs that don't produce
coverage or JUnit XML files, eliminating noisy warnings in every CI run
- Disable coverage upload for Playwright browser integration tests that
only produce JUnit XML

### Jobs cleaned up:

| Job | Issue | Fix |
|-----|-------|-----|
| Node Integration Tests | Coverage disabled in vitest config, custom
reporters without JUnit | Removed codecov step entirely |
| Node-Core Integration Tests | Same as above | Removed codecov step
entirely |
| E2E Tests | Uses ts-node/Playwright, not vitest | Removed codecov step
entirely |
| Remix Tests | Custom vitest config without coverage/JUnit | Removed
codecov step entirely |
| Playwright Browser Tests | No coverage files (Playwright, not vitest)
| Added `enable-coverage: false` |
| PW Loader Tests | Same as above | Added `enable-coverage: false` |

### Warnings eliminated:

- `No coverage files found` (from integration tests, E2E, Remix,
Playwright jobs)
- `No JUnit XML files found matching pattern:
dev-packages/{node,node-core}-integration-tests/**/*.junit.xml`
- `No JUnit XML files found matching pattern:
dev-packages/e2e-tests/**/*.junit.xml`
- `Please ensure your test framework is generating JUnit XML output`
- `Supported formats: clover, cobertura, jacoco, lcov, istanbul, go,
codecov`

### Not addressed (upstream issue):

- `Entity expansion limit exceeded: 100X > 1000` on vitest JUnit XML
files — this is a parser limitation in `getsentry/codecov-action` that
affects large test suites (browser, core, node, nextjs, etc.)

## Test plan

- [ ] CI runs cleanly without the removed warnings
- [ ] Coverage still uploads correctly for Browser Unit Tests and Node
Unit Tests

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>