deps: stop declaring own exporter-trace version

I think exporter-trace is already declared in the google-cloud-shared-config.

Author: suztomo

google-cloud-spanner-executor/pom.xml

@@ -45,7 +45,6 @@
     <dependency>
       <groupId>com.google.cloud.opentelemetry</groupId>
       <artifactId>exporter-trace</artifactId>
-      <version>0.33.0</version>
     </dependency>
     <dependency>
       <groupId>com.google.cloud</groupId>