added loader before showing citation content dialouge

Author: Rohini-Microsoft

src/frontend/src/components/Answer/Answer.tsx

@@ -467,6 +467,35 @@ export const Answer = ({ answer, onCitationClicked }: Props) => {
         </Stack>
       </Dialog>
 
+
+  {isLoadingCitationContent && (
+        <div style={{
+          position: 'fixed',
+          top: 0,
+          left: 0,
+          right: 0,
+          bottom: 0,
+          backgroundColor: 'rgba(0, 0, 0, 0.3)',
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+          zIndex: 1000
+        }}>
+          <div style={{
+            backgroundColor: 'white',
+            padding: '24px',
+            borderRadius: '8px',
+            boxShadow: '0px 14px 28.8px rgba(0, 0, 0, 0.24)',
+            display: 'flex',
+            flexDirection: 'column',
+            alignItems: 'center',
+            gap: '16px'
+          }}>
+            <Spinner size={3} />
+            <Text>Loading citation content...</Text>
+          </div>
+        </div>
+      )}
       {/* New citation content dialog */}
       <Dialog
         onDismiss={closeCitationContentDialog}