Add optional hide/show functionality for environment variable groups

[ehconitin]

Context:

Currently some environment variable groups (like LLM) are completely hidden. However, there are environment groups/subgroups that are rarely accessed but should remain accessible when needed.

Requirements:

• Introduce a configuration to mark environment groups/subgroups as hidden by default

• Add UI controls (e.g. toggle/checkbox) to show/hide these hidden groups

• When hidden, still send group/subgroup metadata (name/description) to display with the toggle control

• Location for config: packages/twenty-server/src/engine/core-modules/environment/constants/environment-variables-hidden-groups.ts

Implementation Notes:

• Similar to how LLM group is currently hidden

• Will need to extend the current hidden groups implementation to support optional visibility

To Figure Out:

Storage mechanism for user visibility preferences (persistence between sessions)