metrics: Don't collect metrics on DEPOT_TOOLS_METRICS=0

Before crrev.com/c/2876082, DEPOT_TOOLS_METRICS=0 was the
env var used to disable metrics collection.

Bug: b/191388102
Change-Id: I0db9d034562f2eb1afb53818b3853cef50c09826
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2980230
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Jack Neus <jackneus@google.com>
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Jack Neus <jackneus@google.com>

metrics_utils.py

@@ -25,7 +25,9 @@ CURRENT_VERSION = 2
 APP_URL = 'https://cit-cli-metrics.appspot.com'
 
 REPORT_BUILD = os.getenv('DEPOT_TOOLS_REPORT_BUILD')
-COLLECT_METRICS = os.getenv('DEPOT_TOOLS_COLLECT_METRICS') != '0'
+COLLECT_METRICS = (
+    os.getenv('DEPOT_TOOLS_COLLECT_METRICS') != '0'
+    and os.getenv('DEPOT_TOOLS_METRICS') != '0')
 
 SYNC_STATUS_SUCCESS = 'SYNC_STATUS_SUCCESS'
 SYNC_STATUS_FAILURE = 'SYNC_STATUS_FAILURE'