[fix] inject registry as plain values to fix CEL validation

[Fkuloff]

Overview

InjectRegistryValue wrote the *Registry struct straight into the module values tree; it now writes a plain map[string]any with the same JSON shape.

What this PR does / why we need it

CEL validation of x-deckhouse-validations converts values with structpb, which accepts only maps, slices and scalars, so every hook values patch failed with convert values to struct: proto: invalid type: *modules.Registry. It hits any module that has a root-level validation rule and an injected registry, i.e. every module delivered from a ModuleSource.

The typed pointer reached the validator because calculateResultValues leaves the merged map as is while there are no patches yet — ApplyValuesPatch returns early — so the first patch of the first hook already failed and the module never converged.

Special notes for your reviewer

ca stays omitted when empty, mirroring the omitempty tag, so rendered values and their checksum do not change.