Add rsvg-convert availability check in convertIconsToImages function to prevent errors when the command is not found

.build/helpers.mjs

@@ -553,6 +553,17 @@ export const getCompileOptions = () => {
 };
 
 export const convertIconsToImages = async (dir, extension, size = 240) => {
+  const rsvgConvertAvailable = await new Promise((resolve) => {
+    exec('command -v rsvg-convert', (error) => {
+      resolve(!error);
+    });
+  });
+
+  if (!rsvgConvertAvailable) {
+    console.log(`\nWarning: rsvg-convert not found. Skipping ${extension} conversion.`);
+    return;
+  }
+
   const icons = getAllIcons();
 
   await asyncForEach(Object.entries(icons), async function ([type, svgFiles]) {