fix(plugins/browser): carry forward requests.RequestException wrapping

PR #25580 was authored before #2746 landed on main, so its plugin
versions of browser_use/browserbase/firecrawl ship without the
requests.RequestException → RuntimeError wrapping that 13c72fb4 added
to the legacy tools/browser_providers/ files for #2746. Cherry-picking
the PR + git rm'ing the legacy files (the migration's intent) would
silently revert that network-error fix.

Port the same try/except pattern into the three plugin create_session()
methods. Browser Use managed-mode keeps its raw-exception propagation
(idempotency-key retry semantics).

Co-authored-by: nidhi-singh02 <nidhi2894@gmail.com>

plugins/browser/browser_use/provider.py

@@ -198,12 +198,22 @@ class BrowserUseBrowserProvider(BrowserProvider):
             else {}
         )
 
-        response = requests.post(
-            f"{config['base_url']}/browsers",
-            headers=headers,
-            json=payload,
-            timeout=30,
-        )
+        try:
+            response = requests.post(
+                f"{config['base_url']}/browsers",
+                headers=headers,
+                json=payload,
+                timeout=30,
+            )
+        except requests.RequestException as exc:
+            # Managed mode: propagate raw so callers can retry with the
+            # preserved idempotency key. Direct mode: wrap network failures
+            # into a clean RuntimeError for end users.
+            if managed_mode:
+                raise
+            raise RuntimeError(
+                f"Browser Use API connection failed: {exc}"
+            ) from exc
 
         if not response.ok:
             if managed_mode and not _should_preserve_pending_create_key(response):