[SPARK-53714] Remove okhttp3 dependency

### What changes were proposed in this pull request?

This PR aims to remove `okhttp3` dependency.

### Why are the changes needed?

As of now, `Apache Spark K8s Operator` does not use this.

### Does this PR introduce _any_ user-facing change?

No behavior change.

### How was this patch tested?

Pass the CIs.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #346 from dongjoon-hyun/SPARK-53714.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

gradle/libs.versions.toml

@@ -26,7 +26,6 @@ log4j = "2.24.3"
 junit = "5.13.4"
 jacoco = "0.8.13"
 mockito = "5.18.0"
-okhttp = "4.12.0"
 
 # Build Analysis
 checkstyle = "10.23.1"
@@ -45,7 +44,6 @@ kubernetes-httpclient-vertx = { group = "io.fabric8", name = "kubernetes-httpcli
 kubernetes-server-mock = { group = "io.fabric8", name = "kubernetes-server-mock", version.ref = "fabric8" }
 kube-api-test-client-inject = {group = "io.fabric8", name = "kube-api-test-client-inject", version.ref = "fabric8"}
 crd-generator-apt = { group = "io.fabric8", name = "crd-generator-apt", version.ref = "fabric8" }
-mockwebserver = { group = "com.squareup.okhttp3", name = "mockwebserver", version.ref = "okhttp" }
 lombok = { group = "org.projectlombok", name = "lombok", version.ref = "lombok" }
 log4j-api = { group = "org.apache.logging.log4j", name = "log4j-api", version.ref = "log4j" }
 log4j-core = { group = "org.apache.logging.log4j", name = "log4j-core", version.ref = "log4j" }

spark-operator/build.gradle

@@ -65,9 +65,6 @@ dependencies {
     exclude group: "org.apache.logging.log4j"
     exclude group: "org.slf4j"
   }
-  testImplementation(libs.mockwebserver) {
-    exclude group: 'junit'
-  }
   testImplementation platform(libs.junit.bom)
   testImplementation(libs.junit.jupiter)
   testRuntimeOnly(libs.junit.platform.launcher)