fix errors details for zonal resize request & align with mixer errors details

[chayankumar999]

This PR contains the bugfix of the followoing issue hashicorp/terraform-provider-google#19917.
Apart from the bugfix, there are some small refactoring which was suggested by the reviewer when adding regional resize request resource to the terraform.

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compute: fix errors details for zonal resize request & align with mixer errors details 

[github-actions]

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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 ( 3 files changed, 144 insertions(+), 143 deletions(-))
google-beta provider: Diff ( 3 files changed, 144 insertions(+), 143 deletions(-))
Open in Cloud Shell: Diff ( 1 file changed, 2 insertions(+), 2 deletions(-))

[modular-magician]

Tests analytics

Total tests: 1076
Passed tests: 1002
Skipped tests: 73
Affected tests: 1

Click here to see the affected service packages

• compute

Action taken

Found 1 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

• TestAccComputeResizeRequest_computeMigResizeRequestExample

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[modular-magician]

🟢 Tests passed during RECORDING mode:
TestAccComputeResizeRequest_computeMigResizeRequestExample [Debug log]

🟢 No issues found for passed tests after REPLAYING rerun.

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🟢 All tests passed!

View the build log or the debug log for each test