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)).

crates/ui/src/styles/color.rs

@@ -15,6 +15,7 @@ pub enum Color {
     Info,
     Modified,
     Conflict,
+    Ignored,
     Muted,
     Placeholder,
     Player(u32),
@@ -31,6 +32,7 @@ impl Color {
             Color::Created => cx.theme().status().created,
             Color::Modified => cx.theme().status().modified,
             Color::Conflict => cx.theme().status().conflict,
+            Color::Ignored => cx.theme().status().ignored,
             Color::Deleted => cx.theme().status().deleted,
             Color::Disabled => cx.theme().colors().text_disabled,
             Color::Hidden => cx.theme().status().hidden,