Use defined type instead of cast

Co-authored-by: Alexander Brandon Coles <[email protected]>

Author: akabiru

app/components/primer/open_project/avatar_fallback.ts

@@ -10,15 +10,15 @@ export class AvatarFallbackElement extends HTMLElement {
     // keeps its default gray fill defined in the source and no color override is applied.
     if (!this.uniqueId || !this.altText) return
 
-    const img = this.querySelector('img[src^="data:image/svg+xml"]')
+    const img = this.querySelector<HTMLImageElement>('img[src^="data:image/svg+xml"]')
     if (!img) return
 
     // Generate consistent color based on uniqueId and altText (hash must match OP Core)
     const text = `${this.uniqueId}${this.altText}`
     const hue = this.valueHash(text)
     const color = `hsl(${hue}, 50%, 30%)`
 
-    this.updateSvgColor(img as HTMLImageElement, color)
+    this.updateSvgColor(img, color)
   }
 
   /*