Drop IAM resources from EkmConnection tests.

[tdbhacks]

This should fix issue #17535, the IAM permissions are being reset after each run but the test passed when permissions were granted manually.

Release Note Template for Downstream PRs (will be copied)

[github-actions]

Hello! I am a robot. Tests will require approval from a repository maintainer to run.

@zli82016, a repository maintainer, has been assigned to review your changes. If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.

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[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.

google provider: Diff ( 1 file changed, 3 insertions(+), 31 deletions(-))
google-beta provider: Diff ( 1 file changed, 3 insertions(+), 31 deletions(-))

[modular-magician]

Tests analytics

Total tests: 33
Passed tests: 29
Skipped tests: 4
Affected tests: 0

Click here to see the affected service packages

• kms

$\textcolor{green}{\textsf{All tests passed!}}$
View the build log

[tdbhacks]

@c2thorn FYI