Call uninit in stop function to avoid AlreadyRunning error

[duanyytop]

static INITIALIZED: once_cell::sync::Lazy<Mutex<bool>> =
    once_cell::sync::Lazy::new(|| Mutex::new(false));

#[cfg(test)]
async fn uninit() {
    let mut init = INITIALIZED.lock().await;
    *init = false;
}

impl MutinyWallet {
    pub async fn new(
    ...
    ) {
        ...
        if *init {
             return Err(MutinyJsError::AlreadyRunning);
         } else {
             *init = true;
         }
         ...
   }     
}