insolvency_proceding: fix missing init script

This portal type refered a non existant init script, which prevents
adding documents of this type.

bt5/erp5_insolvency_proceeding/PortalTypeTemplateItem/portal_types/Claim%20Declaration%20Line.xml

@@ -40,7 +40,7 @@
         </item>
         <item>
             <key> <string>init_script</string> </key>
-            <value> <string>ClaimDeclarationLine_init</string> </value>
+            <value> <string></string> </value>
         </item>
         <item>
             <key> <string>permission</string> </key>