Bug 41795: (follow-up) add a phrase Zebra index for 'authtype'

As per https://software.indexdata.com/zebra/doc/querymodel-rpn.html#querymodel-bib1-completeness:
"[...] Complete field (3) triggers search and scan in index type="p"."

The UNIMARC Zebra index definitions for authorities *do* include
a 'p' (short for 'phrase') type index for authtype -- however, the
MARC21 Zebra index definitions don't and this is causing these two
tests to fail:

t/db_dependent/Biblio.t
t/db_dependent/FrameworkPlugin.t

This patch fixes that.

Test plan for KTD:

1) Apply the patch, then:

   k$ sudo cp etc/zebradb/marc_defs/marc21/authorities/authority-koha-indexdefs.xml /etc/koha/zebradb/marc_defs/marc21/authorities/
   k$ sudo cp etc/zebradb/marc_defs/marc21/authorities/authority-zebra-indexdefs.xsl /etc/koha/zebradb/marc_defs/marc21/authorities/
   k$ koha-rebuild-zebra --authorities --full --force --verbose kohadev

2) Run these tests -- they should both complete without warnings/errors:

   k$ prove -v t/db_dependent/Biblio.t
   k$ prove -v t/db_dependent/FrameworkPlugin.t

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

etc/zebradb/marc_defs/marc21/authorities/authority-koha-indexdefs.xml

@@ -643,5 +643,6 @@ authority-zebra-indexdefs.xsl`
   
   <kohaidx:index_subfields tag="942" subfields="a">
     <kohaidx:target_index>authtype:w</kohaidx:target_index>
+    <kohaidx:target_index>authtype:p</kohaidx:target_index>
   </kohaidx:index_subfields>
 </kohaidx:index_defs>

etc/zebradb/marc_defs/marc21/authorities/authority-zebra-indexdefs.xsl

@@ -176,7 +176,7 @@ definition file (probably something like {biblio,authority}-koha-indexdefs.xml)
   <xslo:template mode="index_subfields" match="marc:datafield[@tag='942']">
     <xslo:for-each select="marc:subfield">
       <xslo:if test="contains('a', @code)">
-        <z:index name="authtype:w">
+        <z:index name="authtype:w authtype:p">
           <xslo:value-of select="."/>
         </z:index>
       </xslo:if>