feat(core): add onDestroy method to OhbugExtension

Author: xinyao27

packages/ohbug-core/src/client.ts

@@ -101,6 +101,7 @@ implements OhbugClient {
         'background:#FF6F61; padding: 2px 1px; color: #FFF',
         'background:transparent',
       )
+      this.__extensions.forEach(extension => extension.onDestroy?.(this))
       return this.__destroy?.()
     }
   }

packages/ohbug-types/src/extension.d.ts

@@ -4,6 +4,7 @@ import type { OhbugEventWithMethods } from './event'
 export interface OhbugExtension {
   name: string
   onSetup?: (client: OhbugClient) => void
+  onDestroy?: (client: OhbugClient) => void
   onEvent?: <D = any>(
     event: OhbugEventWithMethods<D>,
     client: OhbugClient