[WebOTP] Add missing enum for Blink.Sms.Receive.Outcome

This patch adds "Aborted" to the metric as a valid enum.

Change-Id: I78f9f70f1e8ab384718c4d35bd2e5bb703a6601d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2373396Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801245}

tools/metrics/histograms/enums.xml

@@ -66020,6 +66020,7 @@ https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_2.7.1.pdf
   <int value="1" label="Timed out"/>
   <int value="2" label="Connection Error"/>
   <int value="3" label="Cancelled"/>
+  <int value="4" label="Aborted"/>
 </enum>
 
 <enum name="SnackbarIdentifier">