Update the EPPromoCard params to 10 impressions.

A decision was made to lower the number of impressions
from 13 to 10 for the Enhanced Protection Promo Card.

Bug: 1130739
Change-Id: Ib4f960a4c5946a24573adc1b1ff270cddb53ba74
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2691430
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Commit-Queue: Bettina Dea <bdea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#855504}

testing/variations/fieldtrial_testing_config.json

@@ -3179,8 +3179,8 @@
                 {
                     "name": "Enabled",
                     "params": {
-                        "EnhancedProtectionPromoMaxImpressionsAndroid": "13",
-                        "SigninPromoMaxImpressionsAndroid": "13"
+                        "EnhancedProtectionPromoMaxImpressionsAndroid": "10",
+                        "SigninPromoMaxImpressionsAndroid": "10"
                     },
                     "enable_features": [
                         "EnhancedProtectionPromoCard"