bash-completion.sh script not running (Asus RT-AX53U)

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- [x] I checked to make sure that this issue has not already been filed

### AdGuard VPN CLI version

adguardvpn-cli-1.2.37-linux-mipsel.tar.gz

### Environment

- OS: OpenWRT 24.10.0 r28427-6df0e3d02a
- Architecture: ramips/mt7621 (mipsel_24kc)

### Issue Details

Steps to reproduce:
1. Follow the installation steps 1-4 described at https://adguard-vpn.cc/kb/ru/adguard-vpn-for-linux/setting-up-on-a-router/openwrt/
2. Run `adguardvpn-cli login` and get an error

> -ash: adguardvpn-cli: not found

3. Run `/opt/adguardvpn_cli/bash-completion.sh` and get an error

> /opt/adguardvpn_cli/bash-completion.sh: line 8: syntax error: unexpected "(" (expecting "}")

### Expected Behavior

_No response_

### Actual Behavior

1. got to use full path `/opt/adguardvpn_cli/adguardvpn-cli` every command
2. adguardvpn-cli not running on startup (got to start in manually via putty every time), but not sure if it's affected by bash-completion.sh or `/etc/init.d/adguardvpn` script example (created on step 7) not applicable to router's architecture

### Screenshots

Screenshot 1


### Additional Information

_No response_