Emdash source with visual editor image upload fix

Fixes:
1. media.ts: wrap placeholder generation in try-catch
2. toolbar.ts: check r.ok, display error message in popover

renovate.json

@@ -0,0 +1,5 @@
+{
+	"$schema": "https://docs.renovatebot.com/renovate-schema.json",
+	"extends": ["github>unjs/renovate-config", ":widenPeerDependencies"],
+	"packageRules": []
+}