fix empty string customization arn passed which causes service throwing validation error

Author: Will-ShaoHua

plugins/amazonq/codewhisperer/jetbrains-community/src/software/aws/toolkits/jetbrains/services/codewhisperer/credentials/CodeWhispererClientAdaptor.kt

@@ -146,7 +146,7 @@ interface CodeWhispererClientAdaptor : Disposable {
         sessionId: String,
         requestId: String,
         language: CodeWhispererProgrammingLanguage,
-        customizationArn: String,
+        customizationArn: String?,
         acceptedCharacterCount: Int,
         unmodifiedAcceptedTokenCount: Int,
     ): SendTelemetryEventResponse
@@ -512,7 +512,7 @@ open class CodeWhispererClientAdaptorImpl(override val project: Project) : CodeW
         sessionId: String,
         requestId: String,
         language: CodeWhispererProgrammingLanguage,
-        customizationArn: String,
+        customizationArn: String?,
         acceptedCharacterCount: Int,
         unmodifiedAcceptedTokenCount: Int,
     ): SendTelemetryEventResponse = bearerClient().sendTelemetryEvent { requestBuilder ->

plugins/amazonq/codewhisperer/jetbrains-community/src/software/aws/toolkits/jetbrains/services/codewhisperer/telemetry/CodeWhispererUserModificationTracker.kt

@@ -264,7 +264,7 @@ class CodeWhispererUserModificationTracker(private val project: Project) : Dispo
                         suggestion.sessionId,
                         suggestion.requestId,
                         CodeWhispererLanguageManager.getInstance().getLanguage(suggestion.vFile),
-                        CodeWhispererModelConfigurator.getInstance().activeCustomization(project)?.arn.orEmpty(),
+                        CodeWhispererModelConfigurator.getInstance().activeCustomization(project)?.arn,
                         suggestion.suggestion.length,
                         getUnmodifiedAcceptedCharsCount(suggestion.suggestion, modifiedSuggestion)
                     )