[docs][appbar] Document correct default values for elevation and square props

[Ad1tya-007]

Closes #47260

Fix: Document correct default values for AppBar elevation and square props

The problem

AppBar inherits elevation and square from Paper, but uses different defaults:

• Paper defaults: elevation: 1, square: false
• AppBar defaults: elevation: 4, square: true

Because these weren’t documented in AppBar’s TypeScript definitions, IntelliSense showed Paper’s defaults instead of AppBar’s, which was confusing.

The solution

Added elevation and square to AppBar’s TypeScript definitions with the correct defaults:

• elevation: default 4 (was showing 1)
• square: default true (was showing false)

What changed

1. Updated AppBar.d.ts to document these props with correct defaults
2. Excluded them from Paper’s type map to avoid conflicts
3. Regenerated PropTypes (automatic)

Result

• IntelliSense shows the correct defaults
• Documentation matches the implementation

I also ran pnpm proptypes and pnpm docs:api respectively to generate proptypes and the API docs

• I have followed (at least) the PR section of the contributing guide.

[mui-bot]

Netlify deploy preview

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Bundle size report

Bundle	Parsed size	Gzip size
@mui/material	0B(0.00%)	0B(0.00%)
@mui/lab	0B(0.00%)	0B(0.00%)
@mui/system	0B(0.00%)	0B(0.00%)
@mui/utils	0B(0.00%)	0B(0.00%)

Details of bundle changes

Generated by 🚫 dangerJS against ed832b3

[ZeeshanTamboli]

Thanks.