Allow for a 3x2 grid layout for the GridLayout component

[vandercloak]

Describe the problem

4-6 participants is our use cases sweat spot. At the moment when there are 5-6 participants, it uses a 3x3 grid layout.

Is it possible to allow for a 3x2 grid layout (or allow us to override the GRID_LAYOUTS variable)?

Describe the proposed solution

Allow for the customizing/overwritting of the layouts OR to add this entry to GRID_LAYOUTS

{
    columns: 3,
    rows: 2,
    name: "3x2",
    minTiles: 5,
    maxTiles: 6,
    minWidth: 700,
    minHeight: 0
},

### Alternatives considered

_No response_

### Importance

I cannot use LiveKit without it

### Additional Information

_No response_