fix: improve connectivity HTML if quota info error

Currently if the provider doesn't support quota info
the HTML displays something like

```
example.com: Connected
Not supported by your provider.
```

It's not clear that "not supported" only refers to quota info.

Author: WofWca

src/scheduler/connectivity.rs

@@ -476,7 +476,8 @@ impl Context {
             };
             match &quota.recent {
                 Err(e) => {
-                    ret += &escaper::encode_minimal(&e.to_string());
+                    // TODO translate "Quota".
+                    ret += &format!("Quota: {}", &*escaper::encode_minimal(&e.to_string()));
                 }
                 Ok(quota) => {
                     if quota.is_empty() {