[BUG] Manufacturer code not used uniformly in the SDK

[andy31415]

Reproduction steps

Generally MEI codes do not seem uniformly used and our examples do not use the XML manufacturerCode at all.

Encoding in places like https://github.com/project-chip/connectedhomeip/blob/master/src/app/zap-templates/templates/app/ids/Attributes.zapt#L17 or Commands or Events use {{asMEI manufacturerCode code}}

however at the same time other places like https://github.com/project-chip/connectedhomeip/blob/master/examples/chip-tool/templates/commands.zapt#L43 just use code without manufacturerCode at all.

#28805 fixes matter IDL generation, however when trying to change UnitTesting and FaultInjection clusters to be manufacturer extensions I found several inconsistencies like the commands above or python code generation.

GitHub hash of the SDK that was being used

cbc3865