Remove ambiguous Truth8.assertThat

Truth8 is deprecated and Truth.assertThat is already imported statically
resulting in:

  error: reference to assertThat is ambiguous

Change-Id: Id36412324142964fa3b8826623cda053bec193b2
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
index f38120b..2034aa6 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
@@ -15,7 +15,6 @@
 package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.Truth8.assertThat;
 import static java.time.temporal.ChronoUnit.MILLIS;
 
 import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
index 3072767..4a86310 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
@@ -15,7 +15,6 @@
 package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.Truth8.assertThat;
 
 import java.util.Optional;
 import org.junit.Test;