Y25-026 - Remove references to unsupported Show My Plates functionality

[StephenHulme]

Describe the Housekeeping
In the Limber Inbox views, there is a checkbox relating to Show My Plates. Checking this tick-box doesn't appear to alter the returned results and no referrences to this functionality existing in operation or Sequencescape code can be found.
Leaving the tick-box there is misleading for users.

• The tick-box (and related code) should be removed.
• The My Plates dropdown option from the Inboxes button should be removed.

Blocking issues
#2169

Additional context
See #2169 for where this has been removed from the Limber API

Pages where this is present:
http://localhost:3001/search/ongoing_plates

• and all the plate options under the Inboxes drop-down from the Limber home page