[cr138][Android] Fixed Nullaway warnings at BraveAutocompleteMediator arround Suppliers

Chromium change:
https://source.chromium.org/chromium/chromium/src/+/f3320136300287a23b1824df8641e5d7919e1d1b

	Android: Consider Supplier @NullMarked

	Change-Id: I1b892f71c1c4a864827760b019e968bf043b0314
	Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6505624

Author: AlexeyBarabash

android/java/org/chromium/chrome/browser/omnibox/suggestions/BraveAutocompleteMediator.java

@@ -8,11 +8,10 @@
 import android.content.Context;
 import android.os.Handler;
 
-import androidx.annotation.Nullable;
-
 import org.chromium.base.Callback;
 import org.chromium.base.supplier.Supplier;
 import org.chromium.build.annotations.NullMarked;
+import org.chromium.build.annotations.Nullable;
 import org.chromium.chrome.browser.brave_leo.BraveLeoPrefUtils;
 import org.chromium.chrome.browser.brave_leo.BraveLeoUtils;
 import org.chromium.chrome.browser.lifecycle.ActivityLifecycleDispatcher;
@@ -44,7 +43,7 @@ class BraveAutocompleteMediator extends AutocompleteMediator
     private static final String LEO_START_WORD_UPPER_CASE = "LEO";
 
     private AutocompleteDelegate mDelegate;
-    private Supplier<Tab> mActivityTabSupplier;
+    private Supplier<@Nullable Tab> mActivityTabSupplier;
 
     /** Will be deleted in bytecode, value from the parent class will be used instead. */
     @SuppressWarnings("NullAway") // Actual instance is at the parent
@@ -60,8 +59,8 @@ public BraveAutocompleteMediator(
             PropertyModel listPropertyModel,
             Handler handler,
             Supplier<ModalDialogManager> modalDialogManagerSupplier,
-            Supplier<Tab> activityTabSupplier,
-            @Nullable Supplier<ShareDelegate> shareDelegateSupplier,
+            Supplier<@Nullable Tab> activityTabSupplier,
+            Supplier<ShareDelegate> shareDelegateSupplier,
             LocationBarDataProvider locationBarDataProvider,
             Callback<Tab> bringTabToFrontCallback,
             Supplier<TabWindowManager> tabWindowManagerSupplier,