fix(starlette framework tests): unpin sqlalchemy (#4801)

## Description
The starlette framework tests currently pin sqlalchemy to 1.4.41 due to
an upstream issue which has now closed:
encode/databases#512. It looks like we can
unpin this dependency.

Note: this also indirectly fixes the failing starlette framework tests
due to this now closed upstream issue:
encode/databases#513, where sqlalchemy==1.4.42
added a new private field in the SQLAlchemy cursor class. While this job
uses the latest databases package that has accounted for this field,
this was causing attribute errors since we were using a previous version
of sqlalchemy that did not yet have that private field added.


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## Checklist
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## Motivation
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## Reviewer Checklist
- [x] Title is accurate.
- [x] Description motivates each change.
- [x] No unnecessary changes were introduced in this PR.
- [x] Avoid breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
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included in the code or PR.
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- [x] All relevant GitHub issues are correctly linked.
- [x] Backports are identified and tagged with Mergifyio.

.github/workflows/test_frameworks.yml

@@ -309,9 +309,6 @@ jobs:
         run: pip install ../ddtrace
       - name: Install dependencies
         run: scripts/install
-      - name: Pin SQLAlchemy
-        # https://github.com/encode/databases/issues/512
-        run: pip install "SQLAlchemy==1.4.41"
       #Parameters for keyword expression skip 3 failing tests that are expected due to asserting on headers. The errors are because our context propagation headers are being added
       #test_staticfiles_with_invalid_dir_permissions_returns_401 fails with and without ddtrace enabled
       - name: Run tests