Use field identifiers when code gen struct items (#12222)

* Use field identifiers when code gen struct items

Field identifiers were not being used. Instead, the order of field
identifiers was used, with ordinal (0 to N-1) indexes.

This is likely true of other code generated elements, but this PR only
fixes it for struct items.

This PR requires PR #326 in the third_party/zap/repo to function,
as that PR actually includes the field identifier in the query
results.

Tested by running Matter cert tests, and also by inspecting the
generated code for correctness.

* Update zap submodule to latest

* Update a few generated zap files

Re-ran cert tests.

* Restyling

Why are we styling generated code?!

* Revert zap repo update

* Update zap to latest zap version

* Regen zap with the new zap version

Co-authored-by: Andrei Litvin <andy314@gmail.com>

src/app/zap-templates/templates/app/cluster-objects.zapt

@@ -54,7 +54,7 @@ namespace Structs {
 namespace {{asUpperCamelCase name}} {
     enum class Fields {
     {{#zcl_struct_items}}
-    k{{asUpperCamelCase label}} = {{index}},
+    k{{asUpperCamelCase label}} = {{fieldIdentifier}},
     {{/zcl_struct_items}}
     };