refactor(provider): remove google-vertex-anthropic special case in getSDK

This workaround is no longer needed since models.dev has been updated to return the correct npm package path (@ai-sdk/google-vertex/anthropic) for this provider.

Author: MichaelYochpaz

packages/opencode/src/provider/provider.ts

@@ -1023,12 +1023,9 @@ export namespace Provider {
         })
       }
 
-      // Special case: google-vertex-anthropic uses a subpath import
-      const bundledKey =
-        model.providerID === "google-vertex-anthropic" ? "@ai-sdk/google-vertex/anthropic" : model.api.npm
-      const bundledFn = BUNDLED_PROVIDERS[bundledKey]
+      const bundledFn = BUNDLED_PROVIDERS[model.api.npm]
       if (bundledFn) {
-        log.info("using bundled provider", { providerID: model.providerID, pkg: bundledKey })
+        log.info("using bundled provider", { providerID: model.providerID, pkg: model.api.npm })
         const loaded = bundledFn({
           name: model.providerID,
           ...options,