Add env var when CLI is run from language-server (#848)

Author: aswamy

.changeset/orange-experts-work.md

@@ -0,0 +1,5 @@
+---
+'@shopify/theme-language-server-node': patch
+---
+
+[internal] Add env var when CLI command is run

packages/theme-language-server-node/src/metafieldDefinitions.ts

@@ -18,6 +18,10 @@ export async function fetchMetafieldDefinitionsForURI(uri: string) {
     await exec(`${path} theme metafields pull`, {
       cwd: new URL(uri),
       timeout: 10_000,
+      env: {
+        ...process.env,
+        SHOPIFY_LANGUAGE_SERVER: '1',
+      },
     });
   } catch (_) {
     // CLI command can break because of incorrect version or not being logged in