fix: remove unintended export keyword from HTTP client functions

Removed the 'export' keyword from the generated HTTP client function
declaration to match the pattern used by all other protocol renderers
(NATS, Kafka, MQTT, AMQP, WebSocket, EventSource), which use separate
export statements at the bottom of the file.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jonaslagoni

src/codegen/generators/typescript/channels/protocols/http/client.ts

@@ -184,7 +184,7 @@ function generateFunctionImplementation(params: {
   const contextDefault = !hasBody && !hasParameters ? ' = {}' : '';
 
   return `${jsDoc}
-export async function ${functionName}(context: ${contextInterfaceName}${contextDefault}): Promise<HttpClientResponse<${replyType}>> {
+async function ${functionName}(context: ${contextInterfaceName}${contextDefault}): Promise<HttpClientResponse<${replyType}>> {
   // Apply defaults
   const config = {
     path: '${requestTopic}',