Don't re-render summary panel when clearing deployer notifications

### QA

To test:

1. Drag and drop the first charm.
2. Click the Deploy button and verify the summary is correct, but don't confirm. Cancel or close the summary.
3. Drag and drop the second charm.
4. Click the Deploy button - used to be you'd get a "no uncommitted changes" message. Now you'll now see the expected list of two services and two units.