Fix whitelist/blacklist priority select values

[csBlackWolf]

This fixes an off-by-one issue in the whitelist/blacklist priority selector of the ispconfig3_wblist plugin.

Before this change, the priority dropdown displayed values 1–10 in Roundcube, but the submitted values were effectively 0–9. As a result:

selecting priority 1 in Roundcube saved priority 0 in ISPConfig
selecting priority 5 in Roundcube saved priority 4 in ISPConfig
selecting priority 10 in Roundcube saved priority 9 in ISPConfig

ISPConfig itself uses priorities 1–10, so the submitted values should match the displayed values.

Cause:
The priority select only defined display labels:

$input_wblistpriority->add(['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']);

This appears to result in submitted option values 0–9.

Fix:
Pass explicit option values matching the labels:

$input_wblistpriority->add(
['1', '2', '3', '4', '5', '6', '7', '8', '9', '10'],
['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']
);

Tested with:

Debian 13
ISPConfig 3.3.1p1
Roundcube 1.6.16+dfsg-0+deb13u1
ispconfig3_roundcube current GitHub version

Test result:

selecting priority 5 in Roundcube now saves priority 5 in ISPConfig
selecting priority 10 in Roundcube now saves priority 10 in ISPConfig

[Churro]

Thanks!