Disable e2e_om_ops_manager_queryable_backup in OM8 e2e variant

[m1kola]

Summary

This pull request introduces a temporary workaround in the .evergreen.yml configuration to address an issue with the queryable backup task in OM8. A new task group is added that excludes the problematic task, and the build variant is updated to use this new group until the issue is resolved in CLOUDP-346008.

Task group adjustments:

• Added a new task group e2e_ops_manager_kind_5_0_only_task_group_without_queryable_backup that omits the queryable backup task, as a temporary measure while the OM8 issue is outstanding.

Build variant updates:

• Updated the build variant to use the new task group instead of the original, with a clear TODO to revert this once the OM8 issue is fixed.

Proof of Work

We still run e2e_om_ops_manager_queryable_backup in OM6 and OM7 build variants, but not in OM8.

Checklist

• Have you linked a jira ticket and/or is the ticket in the title?
• Have you checked whether your jira ticket required DOCSP changes?
• Have you added changelog file?
  • use skip-changelog label if not needed
  • refer to Changelog files and Release Notes section in CONTRIBUTING.md for more details