MINOR: Remove stray quotes from ShareGroupMember toString (#24036)

The `toString` of `ShareGroupMember` appends a stray quote after
`memberEpoch`, `previousMemberEpoch` and `subscribedTopicNames`, which
are not quoted fields.

This patch removes those three quotes.

Reviewers: Sean Quah <squah@confluent.io>

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/modern/share/ShareGroupMember.java

@@ -285,13 +285,13 @@ public class ShareGroupMember extends ModernGroupMember {
     public String toString() {
         return "ShareGroupMember(" +
             "memberId='" + memberId + '\'' +
-            ", memberEpoch=" + memberEpoch + '\'' +
-            ", previousMemberEpoch=" + previousMemberEpoch + '\'' +
+            ", memberEpoch=" + memberEpoch +
+            ", previousMemberEpoch=" + previousMemberEpoch +
             ", state='" + state + '\'' +
             ", rackId='" + rackId + '\'' +
             ", clientId='" + clientId + '\'' +
             ", clientHost='" + clientHost + '\'' +
-            ", subscribedTopicNames=" + subscribedTopicNames + '\'' +
+            ", subscribedTopicNames=" + subscribedTopicNames +
             ", assignedPartitions=" + assignedPartitions +
             ')';
     }