fix(sidecar): default reinstallApp in SetClearStateReinstall; cover non-android clear

Only Dial set reinstallApp, so a Client built another way would nil-deref on Android clear-state. Default it in SetClearStateReinstall too. Add a non-android test so the platform guard has negative coverage: dropping the android check would now fail.

internal/driver/sidecar/client.go

@@ -46,6 +46,9 @@ func (c *Client) SetClearStateReinstall(serial, apkPath string, output io.Writer
 	c.serial = serial
 	c.apkPath = apkPath
 	c.output = output
+	if c.reinstallApp == nil {
+		c.reinstallApp = android.ReinstallApp
+	}
 }
 
 // ForegroundApp reports the foreground package. Only Android is supported (via