Fix OSS build for unavailable Folly type

Summary:
Very recently this catch was added to guard against instances which may yield a malformed json.

Unfortunately, the change requires a newer version of Folly which is not used in OSS.

Reviewed By: antonk52

Differential Revision: D55637338

fbshipit-source-id: 1a3ba3ce3c2bb8c9f93eddb069bfadd6b45cafe7

xplat/Flipper/FlipperConnectionManagerImpl.cpp

@@ -330,8 +330,12 @@ void FlipperConnectionManagerImpl::sendMessage(const folly::dynamic& message) {
       // Skip sending messages that are too large.
       log(e.what());
       return;
-    } catch (json::print_error& e) {
-      // Skip sending messages with invalid K/V
+    } catch (std::runtime_error& e) {
+      // Skip sending messages with invalid K/V.
+      // On newer versions of folly, this will throw a json::print_error.
+      // Because we are using an older version of folly, we need to catch
+      // the more generic std::runtime_error which is the base class for
+      // json::print_error.
       log(e.what());
       return;
     }