DataGrid - MaxWith is ignored

[lastunicorn]

When smaller MaxWidth is set on a grid than its natural width, the value is ignored.

Step 1: Create a DataGrid with a text column containing 50 characters.
Step 2: Set the MaxWidth to 30.
Expected: The width of the rendered DataGrid should be 30.
Actual: The width of the rendered DataGrid is 54 (50 plus the paddings and borders).

Example:
A table like this:

┌────────────────────────────────────────────────────┐
│ Table without colors                               │
├────────────────────────────────────────────────────┤
│ Text                                               │
├────────────────────────────────────────────────────┤
│ Generic types can have multiple generic parameters │
└────────────────────────────────────────────────────┘

When applying a MaxWidth of 30 on it, is expected to be rendered like this:

┌────────────────────────────┐
│ Table without colors       │
├────────────────────────────┤
│ Text                       │
├────────────────────────────┤
│ Generic types can have     │
│ multiple generic           │
│ parameters                 │
└────────────────────────────┘