Fix over-broad .log-table header fix: lh.php/localtx.php are mixed-align

The previous commit (4c58f85f) put class="log-table" on lh.php and
localtx.php too, which forced *every* header left - but only
Time/Mode/Callsign/Target are actually align="left" in those two
files. Source/Duration/Loss/BER have no align attribute at all (plain
<td>), so they were already correctly centered - the blanket fix just
moved the misalignment from the first 4 columns to the last 4.

Replace with a new `.al` class applied only to the specific <th>
elements whose column is genuinely align="left", leaving
Source/Duration/Loss/BER headers on the sitewide centered default to
match their centered data. last_herd.php/local_tx.php are untouched -
every column in those two really is align="left", so table.log-table
(all headers) remains correct there.

mmdvmhost/lh.php

@@ -57,12 +57,12 @@ if ($callsignLookupSvc == "QRZ") { $callsignLookupUrl = "https://www.qrz.com/db/
 
 ?>
 <b><?php echo $lang['last_heard_list'];?></b>
-  <table class="log-table">
+  <table>
     <tr>
-      <th><a class="tooltip" href="#"><?php echo $lang['time'];?> (<?php echo date('T')?>)<span><b>Time in <?php echo date('T')?> time zone</b></span></a></th>
-      <th><a class="tooltip" href="#"><?php echo $lang['mode'];?><span><b>Transmitted Mode</b></span></a></th>
-      <th style="min-width:14ch"><a class="tooltip" href="#"><?php echo $lang['callsign'];?><span><b>Callsign</b></span></a></th>
-      <th><a class="tooltip" href="#"><?php echo $lang['target'];?><span><b>Target, D-Star Reflector, DMR Talk Group etc</b></span></a></th>
+      <th class="al"><a class="tooltip" href="#"><?php echo $lang['time'];?> (<?php echo date('T')?>)<span><b>Time in <?php echo date('T')?> time zone</b></span></a></th>
+      <th class="al"><a class="tooltip" href="#"><?php echo $lang['mode'];?><span><b>Transmitted Mode</b></span></a></th>
+      <th class="al" style="min-width:14ch"><a class="tooltip" href="#"><?php echo $lang['callsign'];?><span><b>Callsign</b></span></a></th>
+      <th class="al"><a class="tooltip" href="#"><?php echo $lang['target'];?><span><b>Target, D-Star Reflector, DMR Talk Group etc</b></span></a></th>
       <th><a class="tooltip" href="#"><?php echo $lang['src'];?><span><b>Received from source</b></span></a></th>
       <th><a class="tooltip" href="#"><?php echo $lang['dur'];?>(s)<span><b>Duration in Seconds</b></span></a></th>
       <th><a class="tooltip" href="#"><?php echo $lang['loss'];?><span><b>Packet Loss</b></span></a></th>