[babel-plugin] CSS `@layer` code containing `@property`

[necolas]

Describe the issue

See react/react-strict-dom#308 (comment)

Although this appears to be valid CSS, it causes a warning in Expo and may be tripping up some CSS validators. If we don't need the @property code in a layer, it might be a good idea to avoid that for now.

| Warning: Unknown at rule: @property (src/app/stylex.css:16:10):
|   14 |
|   15 |  @layer priority1{
| > 16 | @property --backgroundColor { syntax: "*"; inherits: false;}
|      |          ^
|   17 | @property --opacity { syntax: "*"; inherits: false;}
|   18 | @property --transform { syntax: "*"; inherits: false;}
|   19 | :root, .xxw3bu5{--primary100-x1ud21w4:black;--primary200-x19lv8z8:white;}
| Warning: Unknown at rule: @property (src/app/stylex.css:17:10):
|   15 |  @layer priority1{
|   16 | @property --backgroundColor { syntax: "*"; inherits: false;}
| > 17 | @property --opacity { syntax: "*"; inherits: false;}

Expected behavior

Compatibility with Expo would be improved if @property declarations were not nested inside @layer

Steps to reproduce

See above

Test case

No response

Additional comments

No response

[nmn]

If we don't need the @Property code in a layer, it might be a good idea to avoid that for now.

I don't think we do. Same with @keyframes and @position-try.