Add post update 5s sleep to Topic update

[gregorykofman-google]

Description: Adding a post_update sleep time of 5 seconds to the Managed Service for Apache Kafka terraform Topic resource.

Issue: hashicorp/terraform-provider-google#18949

managedkafka: added 5 second wait post `google_managed_kafka_topic` update to fix eventual consistency errors 

[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 ( 1 file changed, 4 insertions(+))
google-beta provider: Diff ( 1 file changed, 4 insertions(+))

[modular-magician]

Tests analytics

Total tests: 5
Passed tests: 5
Skipped tests: 0
Affected tests: 0

Click here to see the affected service packages

• managedkafka

🟢 All tests passed!

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[github-actions]

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