[SEDONA-136] Enable testAsEWKT for Flink

[sekikn]

Did you read the Contributor Guide?

• Yes, I have read Contributor Rules and Contributor Development Guide

Is this PR related to a JIRA ticket?

• Yes, the URL of the assoicated JIRA ticket is https://issues.apache.org/jira/browse/SEDONA-136. The PR name follows the format [SEDONA-XXX] my subject.

What changes were proposed in this PR?

This PR enables testAsEWKT for Flink again, which was accidentally disabled before.

How was this patch tested?

Ran mvn test -pl flink locally and confirmed the number of tests executed was incremented.

Did this PR include necessary documentation updates?

• No, this PR does not affect any public API so no need to change the docs.

[jiayuasu]

To be merged after this PR: https://github.com/apache/incubator-sedona/pull/647