Fix light_theme changes default node background (#5562)

* Fix light_theme changes default node background

This is an issue where the background of nodes which have no background set were being lightened by this switch, when they should be skipped.

Went unnoticed because the only theme using this was the built-in light theme, which used white for node backgrounds anyway.

* Fix bypassed nodes

* nit

* Revert "nit"

This reverts commit e22f03a0e9.

* Revert "Fix bypassed nodes"

This reverts commit 6121634c09.

* Revert "Fix light_theme changes default node background"

This reverts commit 3206973e5a.

* Fix opacity not rendered to default nodes

Also causes bypassed nodes in light mode to once again render in light pink (again).

Not sure when this regression occurred.

* Revert "Fix opacity not rendered to default nodes"

This reverts commit da65a1dbaf.

* Fix backgrounds not adjusting for light mode

src/scripts/app.ts

@@ -650,7 +650,7 @@ export class ComfyApp {
       if (opacity) adjustments.opacity = opacity
 
       if (useColorPaletteStore().completedActivePalette.light_theme) {
-        adjustments.lightness = 0.5
+        if (old_bgcolor) adjustments.lightness = 0.5
 
         // Lighten title bar of colored nodes on light theme
         if (old_color) {