Revert "fix(deps): update dependency com.google.api.grpc:grpc-google-cloud-optimization-v1 to v1.1.8 (googleapis#8313)"

This reverts commit b9553e9.

Author: suztomo

java-optimization/google-cloud-optimization-bom/pom.xml

@@ -71,7 +71,7 @@
       <dependency>
         <groupId>com.google.api.grpc</groupId>
         <artifactId>grpc-google-cloud-optimization-v1</artifactId>
-        <version>1.1.8</version><!-- {x-version-update:grpc-google-cloud-optimization-v1:current} -->
+        <version>1.1.8-SNAPSHOT</version><!-- {x-version-update:grpc-google-cloud-optimization-v1:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.api.grpc</groupId>

java-optimization/pom.xml

@@ -74,7 +74,7 @@
       <dependency>
         <groupId>com.google.api.grpc</groupId>
         <artifactId>grpc-google-cloud-optimization-v1</artifactId>
-        <version>1.1.8</version><!-- {x-version-update:grpc-google-cloud-optimization-v1:current} -->
+        <version>1.1.8-SNAPSHOT</version><!-- {x-version-update:grpc-google-cloud-optimization-v1:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.api.grpc</groupId>