Use ignored color from theme for items ignored by Git (#10038)

This PR updates the color of the label used for Git-aware items to use
the `ignored` color from the theme when the item is ignored by Git.

The built-in themes have had their `ignored` color updated to match
`text.disabled`, as the existing `ignored` color did not sufficiently
differentiate from non-ignored items.

Fixes #9976.

Release Notes:

- Updated items in the project panel to use the `ignored` color from the
theme when they are ignored by Git
([#9976](https://github.com/zed-industries/zed/issues/9976)).

assets/themes/ayu/ayu.json

@@ -111,7 +111,7 @@
         "hint": "#628b80ff",
         "hint.background": "#0d2f4eff",
         "hint.border": "#1b4a6eff",
-        "ignored": "#8a8986ff",
+        "ignored": "#696a6aff",
         "ignored.background": "#313337ff",
         "ignored.border": "#3f4043ff",
         "info": "#5ac1feff",
@@ -480,7 +480,7 @@
         "hint": "#8ca7c2ff",
         "hint.background": "#deebfaff",
         "hint.border": "#c4daf6ff",
-        "ignored": "#8b8e92ff",
+        "ignored": "#a9acaeff",
         "ignored.background": "#dcdddeff",
         "ignored.border": "#cfd1d2ff",
         "info": "#3b9ee5ff",
@@ -849,7 +849,7 @@
         "hint": "#7399a3ff",
         "hint.background": "#123950ff",
         "hint.border": "#24556fff",
-        "ignored": "#9a9a98ff",
+        "ignored": "#7b7d7fff",
         "ignored.background": "#464a52ff",
         "ignored.border": "#53565dff",
         "info": "#72cffeff",