[Android][WebSignin] Add pressing animation to |Learn more| button

This CL adds the pressing animation to |Learn more| button in the
incognito interstitial of the web sign-in flow.

Bug: 1140903
Change-Id: I4181166b228d01aeb6c9d2a8f2495c847e3ed5cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490100
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819847}

chrome/android/java/res/layout/incognito_interstitial_bottom_sheet_view.xml

@@ -27,19 +27,21 @@
         android:gravity="end"
         android:orientation="horizontal">
 
-        <TextView
+        <org.chromium.ui.widget.ButtonCompat
             android:id="@+id/incognito_interstitial_learn_more"
+            style="@style/TextButton"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:text="@string/learn_more"
-            android:textAppearance="@style/TextAppearance.TextMediumThick.Blue" />
+            android:paddingStart="24dp"
+            android:paddingEnd="24dp"
+            android:text="@string/learn_more" />
 
         <org.chromium.ui.widget.ButtonCompat
             android:id="@+id/incognito_interstitial_continue_button"
             style="@style/FilledButton.Flat"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_marginStart="24dp"
+            android:layout_marginStart="16dp"
             android:text="@string/continue_button" />
 
     </LinearLayout>

chrome/android/javatests/src/org/chromium/chrome/browser/signin/AccountPickerBottomSheetRenderTest.java

@@ -81,7 +81,8 @@ public class AccountPickerBottomSheetRenderTest {
                     /* fullName= */ null, /* givenName= */ null);
 
     @Rule
-    public final RenderTestRule mRenderTestRule = RenderTestRule.Builder.withPublicCorpus().build();
+    public final RenderTestRule mRenderTestRule =
+            RenderTestRule.Builder.withPublicCorpus().setRevision(1).build();
 
     @Rule
     public final AccountManagerTestRule mAccountManagerTestRule =