Fix strikethrough and underline in Linux (#27267)

Follow up to #26827 and #24721, which introduced a bug in Linux.

|before|now|
|---|---|

|![image](https://github.com/user-attachments/assets/6471502d-bf92-4808-ad42-9e0c66569d4f)|!![image](https://github.com/user-attachments/assets/ae45510a-8bc9-4f89-90a0-7496842fecb6)|


Release Notes:

- N/A

Co-authored-by: Jason Lee <huacnlee@gmail.com>

crates/gpui/src/text_system/line.rs

@@ -202,7 +202,7 @@ fn paint_line(
 
             for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
                 glyph_origin.x += glyph.position.x - prev_glyph_position.x;
-                if glyph_ix == 0 {
+                if glyph_ix == 0 && run_ix == 0 {
                     first_glyph_x = glyph_origin.x;
                 }