Hide benchmark indicator when user clicks Apply Benchmark

User feedback: Benchmark indicator should disappear entirely once applied,
not just show "Applied" status.

Changes:
- Modified Apply Benchmark button callback to hide the entire indicator
- Removed code that changed text/color and disabled button
- Cleaner UI - indicator completely disappears after applying settings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

main.go

@@ -6307,10 +6307,8 @@ func buildConvertView(state *appState, src *videoSource) fyne.CanvasObject {
 
 			benchmarkApplyBtn = widget.NewButton("Apply Benchmark", func() {
 				state.applyBenchmarkRecommendation(encoder, preset)
-				benchmarkStatus.Text = "Benchmark: Applied"
-				benchmarkStatus.Color = utils.MustHex("#4CE870")
-				benchmarkStatus.Refresh()
-				benchmarkApplyBtn.Disable()
+				// Hide the entire indicator once applied
+				benchmarkIndicator.Hide()
 			})
 			benchmarkApplyBtn.Importance = widget.MediumImportance