Remove deprecated CodyAgentServer.kt (sourcegraph#6361)

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# Based on PR sourcegraph#6293

## Full chain of PRs as of 2024-12-16

* PR sourcegraph#6361:
`mkondratek/chore/drop-deprecated-server` ➔
`mkondratek/migrate-api/testing/requestErrors`
* PR sourcegraph#6293:
  `mkondratek/migrate-api/testing/requestErrors` ➔ `main`

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## Test plan

N/A, code refactoring

## Changelog

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jetbrains/src/integrationTest/resources/recordings/integration-test_2927926756/recording.har.yaml

@@ -324,7 +324,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query CurrentSiteCodyLlmConfiguration {
                   site {
                       codyLLMConfiguration {
@@ -449,7 +449,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query CurrentSiteCodyLlmConfiguration {
                   site {
                       codyLLMConfiguration {
@@ -562,7 +562,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query CurrentSiteCodyLlmProvider {
                   site {
                       codyLLMConfiguration {
@@ -675,7 +675,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query CurrentUser {
                   currentUser {
                       id
@@ -810,7 +810,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query CurrentUserCodySubscription {
                   currentUser {
                       codySubscription {
@@ -933,7 +933,7 @@ log:
           params: []
           textJSON:
             query: |-
-              
+
               query SiteProductVersion {
                   site {
                       productVersion

jetbrains/src/main/kotlin/com/sourcegraph/cody/agent/CodyAgent.kt

@@ -12,6 +12,7 @@ import com.sourcegraph.cody.agent.protocol.*
 import com.sourcegraph.cody.agent.protocol_extensions.ProtocolTextDocumentExt
 import com.sourcegraph.cody.agent.protocol_generated.ClientCapabilities
 import com.sourcegraph.cody.agent.protocol_generated.ClientInfo
+import com.sourcegraph.cody.agent.protocol_generated.CodyAgentServer
 import com.sourcegraph.cody.agent.protocol_generated.ProtocolTypeAdapters
 import com.sourcegraph.cody.agent.protocol_generated.WebviewNativeConfig
 import com.sourcegraph.cody.ui.web.WebUIServiceWebviewProvider