[mysql] collect foreign key delete and update rule

[lu-zhengda]

What does this PR do?

This PR enhances MySQL foreign key metadata collection by including delete and update rules from INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS. These rules define the referential behavior enforced when a referenced row is deleted or updated. Capturing this information is essential for understanding the impact of foreign key constraints on cascading operations. The possible values for delete and update actions are: CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION.

Note: On MariaDB 10.5 or above, the REFERENCES privilege at the table scope is required to view delete_rule and update_rule from INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS.

Motivation

https://datadoghq.atlassian.net/browse/DBMON-5083
The delete and update rules dictate how changes propagate when modifications occurs for a foreign key. Without this information, users reviewing foreign key definitions lack critical context on cascading behaviors. This PR ensures that these actions are captured.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.22%. Comparing base (8ace7d5) to head (53f6038).
Report is 6 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
hive	?
hivemq	?
ignite	?
jboss_wildfly	?
kafka	?
mysql	89.49% <100.00%> (?)
presto	?
solr	?

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