Fix fieldtrial testing config for ButterForPayments stage 2

This config is supposed to enable the account indication footers for
*Save Card* bubbles, not for *Password* bubbles.

Bug: 1121258
Change-Id: I09a4cbc636582c3298d837d356f1274c0d5c36c9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2624787Reviewed-by: Maksim Moskvitin <mmoskvitin@google.com>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842598}

testing/variations/fieldtrial_testing_config.json

@@ -1392,7 +1392,7 @@
                     "name": "Enabled_Stage2",
                     "enable_features": [
                         "AutofillEnableAccountWalletStorage",
-                        "AutofillEnablePasswordInfoBarAccountIndicationFooter"
+                        "AutofillEnableSaveCardInfoBarAccountIndicationFooter"
                     ],
                     "disable_features": [
                         "WalletRequiresFirstSyncSetupComplete"