Bug 38455: UNIMARC XSLT diplay field 036 correctly

In Unimarc, the field for music incipit is 036. The test to display the music player is correctly on field 036 but the field displayed was 031 (which is valid for Marc21 but not for Unimac).

To test:
On a Koha Unimarc instance:
1- Set system preference "OPACPlayMusicalInscripts" to "Play" and "OPACShowMusicalInscripts" to "Show"
2- set the system preference OPACXSLTListsDisplay is set on koha-tmpl/opac-tmpl/bootstrap/{languagecode}/xslt/UNIMARCslim2OPACDetail.xsl
3- Update a framework of your choice to display subfield 036$2 $g $n $o $p in OPAC, intranet and editor (make sure the collapse checkbox is not checked)
4- Create a record with the previously modified framework, fill all mandatory fields and add a 036 field with at least subfield $2 $g $n $o $p, make sure you have no 031 field
example of a valid 036 field
    036$2 pe
    036$g G-2
    036$n bB
    036$o 3/4
    036$p {8C'8C'}/4D4C'4F/2E
5- Go to the OPAC detail page for the record created (with interface in English)
6- check that the music player does not appear
7- apply the patch
8- Reload the OPAC detail page for the record created (sill with interface in English)
9- check that the music player appears and is working

Signed-off-by: Emmanuel Bétemps <e.betemps@gmail.com>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit b364089c70)
Signed-off-by: Paul Derscheid <paul.derscheid@lmscloud.de>

koha-tmpl/opac-tmpl/bootstrap/en/xslt/UNIMARCslim2OPACDetail.xsl

@@ -518,7 +518,7 @@
   <xsl:variable name="OPACPlayMusicalInscripts" select="marc:sysprefs/marc:syspref[@name='OPACPlayMusicalInscripts']" />
 
   <xsl:if test="$OPACShowMusicalInscripts and marc:datafield[@tag=036]">
-      <xsl:for-each select="marc:datafield[@tag=031]">
+      <xsl:for-each select="marc:datafield[@tag=036]">
 
         <span class="results_summary musical_inscripts">
             <xsl:if test="marc:subfield[@code='u']">