node_cache: Run pnpm install if node_modules not present in help-beta.

We need this check when switching between branches without `help-beta`
package. `node_modules` will be removed when working on a non `help-beta`
branch, but if `node_modules/.pnpm/lock.yaml` has not been updated by that
branch, we will end up in a situation where we might not have `node_modules`
even when we run the provision command.

We might not need this check when the `help-beta` initial folder
has been merged for a week or two, where almost all active PRs
would have been rebased upon main, making switching branches an ease.

scripts/lib/node_cache.py

@@ -9,20 +9,31 @@ def setup_node_modules(production: bool = DEFAULT_PRODUCTION) -> None:
     if os.path.islink("node_modules"):
         os.unlink("node_modules")
 
+    skip = False
+
     try:
         with open("node_modules/.pnpm/lock.yaml") as a, open("pnpm-lock.yaml") as b:
             if a.read() == b.read():
-                return
+                skip = True
     except FileNotFoundError:
         pass
 
-    run(
-        [
-            "/usr/local/bin/corepack",
-            "pnpm",
-            "install",
-            "--frozen-lockfile",
-            "--prefer-offline",
-            *(["--prod"] if production else []),
-        ]
-    )
+    # We need this check when switching between branches without `help-beta`
+    # package. `node_modules` will be removed when working on a non `help-beta`
+    # branch, but if `node_modules/.pnpm/lock.yaml` has not been updated by that
+    # branch, we will end up in a situation where we might not have `node_modules`
+    # even when we run the provision command.
+    if not os.path.exists("help-beta/node_modules"):
+        skip = False
+
+    if not skip:
+        run(
+            [
+                "/usr/local/bin/corepack",
+                "pnpm",
+                "install",
+                "--frozen-lockfile",
+                "--prefer-offline",
+                *(["--prod"] if production else []),
+            ]
+        )