fix: Upgrade Spanner samples to OpenCensus 0.25.0 (#2415)

Fixes #2233

Author: dmitry-fa

spanner/cloud-client/pom.xml

@@ -33,7 +33,7 @@ limitations under the License.
     <maven.compiler.target>1.8</maven.compiler.target>
     <maven.compiler.source>1.8</maven.compiler.source>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <opencensus.version>0.23.0</opencensus.version>
+    <opencensus.version>0.25.0</opencensus.version>
   </properties>
 
   <!-- Include the BOM to ensure compatibility across multiple google-cloud-* libraries -->
@@ -63,6 +63,14 @@ limitations under the License.
           <groupId>io.opencensus</groupId>
           <artifactId>opencensus-api</artifactId>
         </exclusion>
+        <exclusion>
+          <groupId>io.grpc</groupId>
+          <artifactId>grpc-netty-shaded</artifactId>
+        </exclusion>
+        <exclusion>
+          <groupId>io.grpc</groupId>
+          <artifactId>grpc-core</artifactId>
+        </exclusion>
       </exclusions>
     </dependency>