webauthn: passkeys are only supported on Android >= P.

BUG=1403291

(cherry picked from commit 52e3bd9)

Change-Id: I4dcfab87907b38c43f5152292e3d66296f910aeb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4122979
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Auto-Submit: Adam Langley <agl@chromium.org>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1087059}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4127289
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5481@{#80}
Cr-Branched-From: 130f3e4-refs/heads/main@{#1084008}

Author: Adam Langley

components/webauthn/android/java/src/org/chromium/components/webauthn/AuthenticatorImpl.java

@@ -225,7 +225,8 @@ public void getMatchingCredentialIds(String relyingPartyId, byte[][] credentialI
     @Override
     public void isConditionalMediationAvailable(
             final IsConditionalMediationAvailable_Response callback) {
-        if (mGmsCorePackageVersion < GMSCORE_MIN_VERSION) {
+        if (mGmsCorePackageVersion < GMSCORE_MIN_VERSION
+                || Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
             callback.call(false);
             return;
         }