refactor(pom): remove redundant conscrypt.version from gax-java

Author: lqiu96

sdk-platform-java/gax-java/pom.xml

@@ -36,7 +36,6 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>1.8</maven.compiler.target>
-    <conscrypt.version>2.6.0</conscrypt.version>
   </properties>
 
   <modules>