QoL improvements to Existing Connectors Admin UI

[bhaverland]

• Adds filter functionality to the Existing Connectors Admin UI
• Adds items per page selector component that uses the CustomDropdown from @/components/Dropdown
• Items per page is now saved in local storage and persists if user navigates away from page.
• Page is set back to page 1 if filter or items per page is changed.

[vercel[bot]]

@bhaverland is attempting to deploy a commit to the Danswer Team on Vercel.

A member of the Team first needs to authorize it.