[TT-7129] Fix setting global_size_limit not enabling RequestSizeLimitMiddleware

[PatrickTaibel]

Description

Fix EnabledForSpec in RequestSizeLimitMiddleware for API global limits without size limits in extended_paths.

Related Issue

#3977

Motivation and Context

Makes the RequestSizeLimitMiddleware usable when only API global limits are specified.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactoring or add test (improvements in base code or adds test coverage to functionality)

Checklist

• Make sure you are requesting to pull a topic/feature/bugfix branch (right side). If pulling from your own
  fork, don't request your master!
• Make sure you are making a pull request against the master branch (left side). Also, you should start
  your branch off our latest master.
• My change requires a change to the documentation.
  • If you've changed APIs, describe what needs to be updated in the documentation.
  • If new config option added, ensure that it can be set via ENV variable
• I have updated the documentation accordingly.
• Modules and vendor dependencies have been updated; run go mod tidy && go mod vendor
• When updating library version must provide reason/explanation for this update.
• I have added tests to cover my changes.
• All new and existing tests passed.
• Check your code additions will not fail linting checks:
  • go fmt -s
  • go vet

[buger]

Nice one!

Keen to add a small test for it?

It can look like this:

func TestValidateJSONSchema(t *testing.T) {
	ts := StartTest(nil)
	defer ts.Close()

	ts.Gw.BuildAndLoadAPI(func(spec *APISpec) {
		UpdateAPIVersion(spec, "v1", func(v *apidef.VersionInfo) {
			v.GlobalSizeLimit = 1
		})
	})

	ts.Run(t, []test.TestCase{
		{Method: "POST", Path: "/sample/", Data: "foobar", Code: http.StatusBadRequest},
	}...)
}

[PatrickTaibel]

I've added a small test for this. Thank you very much for the pretty much finished test snippet!

[titpetric]

Everything LGTM, please rebase and check the test failures.

[PatrickTaibel]

I've rebased the branch onto the current master.
The previous test run seems to have failed on test --- FAIL: TestEnforcedTimeout (4.27s). As far as I can tell, this has nothing to do with the changes in this PR.

[titpetric]

I believe the tests on master have been resolved. Can I ask you for the hopefully last rebase? The teams are improving the test case failures, so your best case at merging this soon is unfortunately rebasing until tests pass 😬

[titpetric]

I've cherry-picked this over #4967 - your contribution will be included in the 5.1 release. Thank you 🏆