ref: Remove Spotlight Django integration in new major

[sentrivana]

Description

See the original potel PR linked in the ticket for more context.

Issues

Closes https://linear.app/getsentry/issue/PY-1938/remove-spotlight-django-integration
Closes #5014

Reminders

• Please add tests to validate your changes, and lint your code using uv run ruff.
• Add GH Issue ID & Linear ID (if applicable)
• PR title should use conventional commit style (feat:, fix:, ref:, meta:)
• For external contributors: CONTRIBUTING.md, Sentry SDK development docs, Discord community

[linear-code]

PY-1938

[github-actions]

Codecov Results 📊

✅ 96224 passed | ⏭️ 6337 skipped | Total: 102561 | Pass Rate: 93.82% | Execution Time: 342m 44s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📉 -3990
Passed Tests	📉 -3545
Failed Tests	📉 -1
Skipped Tests	📉 -444

➖ Removed Tests (1)

View removed tests

• test_continuous_profiler_auto_start_and_stop_sampled_span_streaming[non-experiment-thread]
  • File: tests.profiler.test_continuous_profiler

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2353 uncovered lines.
✅ Project coverage is 90.01%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    89.88%    90.01%    +0.13%
==========================================
  Files          193       186        -7
  Lines        24686     23546     -1140
  Branches      8814      8434      -380
==========================================
+ Hits         22188     21193      -995
- Misses        2498      2353      -145
- Partials      1400      1344       -56

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