feat: add ButtonLoadingIndicator

src/components/Indicators/ButtonLoadingIndicator.tsx

@@ -0,0 +1,16 @@
+import CircularProgress from "@mui/material/CircularProgress";
+
+/**
+ * A loading wheel for buttons to use to show loading state (e.g., for form submit btns).
+ */
+export const ButtonLoadingIndicator = () => (
+  <CircularProgress
+    color="inherit"
+    size={26}
+    style={{
+      position: "absolute",
+      top: "calc(50% - 13px)", // 13px is half the height of the CircularProgress @ size=26
+      left: "calc(50% - 13px)",
+    }}
+  />
+);