Move MetricsHelper to common utils class

[vecheka]

Description

Move MetricsHelper to common utils class instead so it can be used by other connectors.

Testing

Ran the following successfully:

./gradlew :data-prepper-plugins:saas-source-plugins:microsoft-office365-source:test \
--tests "org.opensearch.dataprepper.plugins.source.microsoft_office365.Office365CrawlerClientTest"

./gradlew :data-prepper-plugins:saas-source-plugins:microsoft-office365-source:test \
--tests "org.opensearch.dataprepper.plugins.source.microsoft_office365.Office365RestClientTest"


./gradlew :data-prepper-plugins:saas-source-plugins:microsoft-office365-source:checkstyleTest  

Issues Resolved

N/A

Check List

• [ x ] New functionality includes testing.
• New functionality has a documentation issue. Please link to it in this PR.
  • New functionality has javadoc added
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