Disable OSPolicyAssisgnment sweeper

[roaks3]

This sweeper is failing consistently with a 501, and because of how the retry logic works with a 501, it ends up trying for 6+ minutes and causes our whole sweeper task to timeout.

The 501 appears to come from the location parameter, which is assumed by the DCL to take a region, but it actually only accepts a zone. Passing in a region causes a 501, while passing in a zone succeeds. However, since this fix looks like it could be more involved and require tinkering with the DCL generator, it seems fair to disable the sweeper for now because it doesn't work.

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

[modular-magician]

Oops! It looks like you're using an unknown release-note type in your changelog entries:

• REPLACEME

Please only use the types listed in https://github.com/GoogleCloudPlatform/magic-modules/blob/master/.ci/RELEASE_NOTES_GUIDE.md.

[rileykarson]

fyi @hao-nan-li: no action yet, but this is one of the types of error the sweepers can have for later in the quarter!

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

Terraform GA: Diff ( 1 file changed, 71 deletions(-))
TF Validator: Diff ( 2 files changed, 3 insertions(+), 3 deletions(-))

[modular-magician]

Tests analytics

Total tests: 2378
Passed tests 2128
Skipped tests: 248
Failed tests: 2

Action taken

Triggering VCR tests in RECORDING mode for the tests that failed during VCR. Click here to see the failed tests

TestAccContainerCluster_withInvalidGatewayApiConfigChannel|TestAccBigtableAppProfile_bigtableAppProfileMulticlusterExample

[modular-magician]

Tests passed during RECORDING mode:
TestAccContainerCluster_withInvalidGatewayApiConfigChannel[Debug log]
TestAccBigtableAppProfile_bigtableAppProfileMulticlusterExample[Debug log]

All tests passed
View the build log or the debug log for each test

[roaks3]

I created this issue for tracking a fix hashicorp/terraform-provider-google#13338

[hao-nan-li]

fyi @hao-nan-li: no action yet, but this is one of the types of error the sweepers can have for later in the quarter!

Noted, thanks!