Unmasked default (#4553)

## What type of PR is this? (check all applicable)

- [ ] Refactor
- [ ] Feature
- [ ] Bug Fix
- [ X ] Optimization
- [ ] Documentation Update
- [ ] Community Node Submission


## Have you discussed this change with the InvokeAI team?
- [ X ] Yes
- [ ] No, because:

      
## Have you updated all relevant documentation?
- [ ] Yes
- [ X ] No


## Description
Mask Edge was set to default, and producing poor results. I've updated
the default back to Unmasked.

invokeai/frontend/web/src/features/parameters/store/generationSlice.ts

@@ -80,7 +80,7 @@ export const initialGenerationState: GenerationState = {
   scheduler: 'euler',
   maskBlur: 16,
   maskBlurMethod: 'box',
-  canvasCoherenceMode: 'edge',
+  canvasCoherenceMode: 'unmasked',
   canvasCoherenceSteps: 20,
   canvasCoherenceStrength: 0.3,
   seed: 0,