chore(appsec): remove outdated files from codeowner (#13749)

After PR #13748 we need to
update codeowner file and remove outdated files

## Checklist
- [x] PR author has checked that all the criteria below are met
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- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
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- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
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[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Author: avara1986

.github/CODEOWNERS

@@ -122,9 +122,7 @@ ddtrace/internal/_exceptions.py     @DataDog/asm-python
 ddtrace/internal/appsec/            @DataDog/asm-python
 ddtrace/internal/iast/              @DataDog/asm-python
 tests/appsec/                       @DataDog/asm-python
-tests/contrib/dbapi/test_dbapi_appsec.py    @DataDog/asm-python
 tests/contrib/subprocess            @DataDog/asm-python
-tests/contrib/flask/test_flask_appsec.py    @DataDog/asm-python
 tests/snapshots/tests*appsec*.json  @DataDog/asm-python
 tests/contrib/*/test*appsec*.py     @DataDog/asm-python
 scripts/iast/*                      @DataDog/asm-python