Fix name for SCTAuditing report success histogram

Update the histogram definition for the SCT auditing report success
histogram to "Security.SCTAuditing.OptIn.ReportSucceeded" (as actually
emitted by the code).

Change-Id: I1562cb2b5c1a9c08904b0249960d664af6a4b720
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522333
Commit-Queue: Chris Thompson <cthomp@chromium.org>
Commit-Queue: Emily Stark <estark@chromium.org>
Auto-Submit: Chris Thompson <cthomp@chromium.org>
Reviewed-by: Emily Stark <estark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825124}

tools/metrics/histograms/histograms_xml/security/histograms.xml

@@ -476,7 +476,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
-<histogram name="Security.SCTAuditing.OptIn.ReportSuccess" enum="Boolean"
+<histogram name="Security.SCTAuditing.OptIn.ReportSucceeded" enum="Boolean"
     expires_after="M92">
   <owner>cthomp@chromium.org</owner>
   <owner>security-enamel@chromium.org</owner>