gpui: Add support for text in SVGs (#26335)

Closes #21319
Before: 

![image](https://github.com/user-attachments/assets/f75d7d59-75b1-4836-ae3b-6a1f526a5833)
After:

![image](https://github.com/user-attachments/assets/5fa28a6d-c417-4777-99f8-2a17edf759a0)

Use fontdb to load system fonts and pass it to resvg renderer. This adds
a small increase in startup time (around 30ms on my Linux system to
traverse fonts on a cold start). In the future once cosmic-text bumps
their version of fontdb we could clone the Database from
CosmicTextSystem

Release Notes: 
- Added: support for rendering text in SVGs

crates/gpui/src/svg_renderer.rs

@@ -1,7 +1,10 @@
 use crate::{AssetSource, DevicePixels, IsZero, Result, SharedString, Size};
 use anyhow::anyhow;
 use resvg::tiny_skia::Pixmap;
-use std::{hash::Hash, sync::Arc};
+use std::{
+    hash::Hash,
+    sync::{Arc, LazyLock},
+};
 
 /// When rendering SVGs, we render them at twice the size to get a higher-quality result.
 pub const SMOOTH_SVG_SCALE_FACTOR: f32 = 2.;
@@ -15,6 +18,7 @@ pub(crate) struct RenderSvgParams {
 #[derive(Clone)]
 pub struct SvgRenderer {
     asset_source: Arc<dyn AssetSource>,
+    usvg_options: Arc<usvg::Options<'static>>,
 }
 
 pub enum SvgSize {
@@ -24,7 +28,31 @@ pub enum SvgSize {
 
 impl SvgRenderer {
     pub fn new(asset_source: Arc<dyn AssetSource>) -> Self {
-        Self { asset_source }
+        let font_db = LazyLock::new(|| {
+            let mut db = usvg::fontdb::Database::new();
+            db.load_system_fonts();
+            Arc::new(db)
+        });
+        let default_font_resolver = usvg::FontResolver::default_font_selector();
+        let font_resolver = Box::new(
+            move |font: &usvg::Font, db: &mut Arc<usvg::fontdb::Database>| {
+                if db.is_empty() {
+                    *db = font_db.clone();
+                }
+                default_font_resolver(font, db)
+            },
+        );
+        let options = usvg::Options {
+            font_resolver: usvg::FontResolver {
+                select_font: font_resolver,
+                select_fallback: usvg::FontResolver::default_fallback_selector(),
+            },
+            ..Default::default()
+        };
+        Self {
+            asset_source,
+            usvg_options: Arc::new(options),
+        }
     }
 
     pub(crate) fn render(&self, params: &RenderSvgParams) -> Result<Option<Vec<u8>>> {
@@ -49,7 +77,7 @@ impl SvgRenderer {
     }
 
     pub fn render_pixmap(&self, bytes: &[u8], size: SvgSize) -> Result<Pixmap, usvg::Error> {
-        let tree = usvg::Tree::from_data(bytes, &usvg::Options::default())?;
+        let tree = usvg::Tree::from_data(bytes, &self.usvg_options)?;
 
         let size = match size {
             SvgSize::Size(size) => size,