[horde] disable preview for zip files

[A. Schulze]

Hello,

I've a message with one large archive (40 MB) containing thousands of  
small files.
Horde IMP needs more then a minute to show the message.

``` ( german ...)
Archivname: anlage.zip
Archivgröße: 35000150 bytes
Anzahl: 2976 Dateien

                 Attribute     Größe     Änderungsdatum   MethodeVerhältnis
--------------------------------------------------------------------------
datei1...           -A---     16665  13-Jan-2022 14:45  Deflated     63,7%
datei2...           -A---     16653  13-Jan-2022 14:45  Deflated     63,9%
datei3...           -A---     16719  13-Jan-2022 14:45  Deflated     64,3%
...
--------------------------------------------------------------------------
```


I like to let horde not display this archive listing as I expect
generating this listing is time consuming.

# cat /etc/horde/imp/mime_drivers.local.php
<?php
$mime_drivers['zip']['limit_inline_size'] = 1048576;

// see  
https://github.com/horde/imp/blob/8d19f07d87a6320df5de6b293ec05a49502005ff/config/mime_drivers.php#L173
$mime_drivers['zip']['show_contents'] = false;

$mime_drivers['zip']['inline'] = false;

// end

None of these three setting for it's own change anything.
Where is my fault? Any hints are welcome.

Andreas