Changed GuildMemberManager.search to use new endpoint

[Lixqa]

This PR refactors the GuildMemberManager.search method to use Discord's new /members-search endpoint, replacing the older search logic. The updated system allows for advanced, flexible, and structured member querying, using logical and range-based filters.

Using new query system:

• "or" and "and" blocks
• Range filters (gte/lte) for dates
• Logical filters (or/and) for usernames, roles, and more
• Support for internal safety signal filters

Why?

• Greater flexibility
• Enables precise user searches for bots, tools, and dashboards

[VillainsRule]

does this work if the user isn't a mod/admin?

[Lixqa]

does this work if the user isn't a mod/admin?

Nope, it requires access to the member safety.

[VillainsRule]

does this work if the user isn't a mod/admin?

Nope, it requires access to the member safety.

that's a problem