`ui._remote_ctl`: shield remote rect removals

Since under `trio`-cancellation the `.remove()` is a checkpoint and will
be masked by a taskc AND we **always want to remove the rect** despite
the surrounding teardown conditions.

piker/ui/_remote_ctl.py

@@ -15,8 +15,8 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 '''
-Remote control tasks for sending annotations (and maybe more cmds)
-to a chart from some other actor.
+Remote control tasks for sending annotations (and maybe more cmds) to
+a chart from some other actor.
 
 '''
 from __future__ import annotations
@@ -32,6 +32,7 @@ from typing import (
 )
 
 import tractor
+import trio
 from tractor import trionics
 from tractor import (
     Portal,
@@ -316,7 +317,9 @@ class AnnotCtl(Struct):
             )
             yield aid
         finally:
-            await self.remove(aid)
+            # async ipc send op
+            with trio.CancelScope(shield=True):
+                await self.remove(aid)
 
     async def redraw(
         self,