refactor(predict): extract user trait setting into dedicated method

- Create private setPolymarketAccountCreatedTrait() method
- Use .catch() for proper async error handling (fire-and-forget pattern)
- Clean separation of concerns with descriptive method name
- Non-blocking trait setting with error logging to Sentry
- All 169 tests passing

Author: andrepimenta

app/components/UI/Predict/providers/polymarket/PolymarketProvider.ts

@@ -1300,6 +1300,32 @@ export class PolymarketProvider implements PredictProvider {
     return result;
   }
 
+  /**
+   * Set user trait for Polymarket account creation via MetaMask
+   * Fire-and-forget operation that logs errors but doesn't fail
+   */
+  private setPolymarketAccountCreatedTrait(): void {
+    MetaMetrics.getInstance()
+      .addTraitsToUser({
+        [UserProfileProperty.CREATED_POLYMARKET_ACCOUNT_VIA_MM]: true,
+      })
+      .catch((error) => {
+        // Log error but don't fail the deposit preparation
+        Logger.error(error as Error, {
+          tags: {
+            feature: PREDICT_CONSTANTS.FEATURE_NAME,
+            provider: 'polymarket',
+          },
+          context: {
+            name: 'PolymarketProvider',
+            data: {
+              method: 'setPolymarketAccountCreatedTrait',
+            },
+          },
+        });
+      });
+  }
+
   public async prepareDeposit(
     params: PrepareDepositParams & { signer: Signer },
   ): Promise<PrepareDepositResponse> {
@@ -1344,27 +1370,7 @@ export class PolymarketProvider implements PredictProvider {
       transactions.push(deployTransaction);
 
       // Set user trait for Polymarket account creation via MetaMask
-      try {
-        const metrics = MetaMetrics.getInstance();
-        await metrics.addTraitsToUser({
-          [UserProfileProperty.CREATED_POLYMARKET_ACCOUNT_VIA_MM]: true,
-        });
-      } catch (error) {
-        // Log error but don't fail the deposit preparation
-        Logger.error(error as Error, {
-          tags: {
-            feature: PREDICT_CONSTANTS.FEATURE_NAME,
-            provider: 'polymarket',
-          },
-          context: {
-            name: 'PolymarketProvider',
-            data: {
-              method: 'prepareDeposit',
-              action: 'setPolymarketAccountTrait',
-            },
-          },
-        });
-      }
+      this.setPolymarketAccountCreatedTrait();
     }
 
     if (!accountState.hasAllowances) {