Issue & blob aggregations for group searches do not use traversal_ids

What does this MR do and why?

Add group_ids in the base_options for Gitlab::Elastic::GroupSearchResults. I think it makes sense to add group_id in base_options for group level search. With this change aggregation end point will get the group_ids and therefore traversal_ids filter will be added.

In ee/lib/gitlab/elastic/search_results.rb have to use base_options.reverse_merge(group_ids: group_ids) because merge was overwriting the group_ids for the group level search. With the reverse_merge it will not overwrite the group_ids which can be added only in the case of group level search. And for global search group_ids will be added as a new key.

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Before	After

How to set up and validate locally

• Ensure Elasticsearch is enabled
• Perform a Group level code search
• Select the aggregations endpoint from the performance bar for ES queroies
• Verify that blob:authorized:namespace:ancestry_filter exists

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #416129 (closed)