[Bug]: Interfaces for FabricConfig are misaligned throughout Fluent.

Library

React / v8 (@fluentui/react)

System Info

System:
    OS: Windows 10 10.0.22000
    CPU: (12) x64 Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
    Memory: 8.75 GB / 31.94 GB
  Browsers:
    Edge: Spartan (44.22000.120.0), Chromium (106.0.1370.34)
    Internet Explorer: 11.0.22000.120

NOTE: I'm on Win11 Pro not 10

Are you reporting Accessibility issue?

no

Reproduction

N/A - compiler error

Bug Description

Interfaces and uses of FabricConfig are not lined up properly. If a consumer imports font-icons-mdl2 they'll get the global defined within that file and this cannot be overridden (TS feature request: https://github.com/microsoft/TypeScript/issues/36146).

Actual Behavior

If font-icons-mdl2 is imported, the window.FabricConfig interface is set globally. Unfortunately, this then doesn't align with the expected interface that Stylesheet.ts uses. As a result teams downstream doing more complex things or attempting to pull this config are stuck just @ts-ignore'ing their own globals to get around the problem.

Global from Fluent:

https://github.com/microsoft/fluentui/blob/6112cd720c2a15635eae7175f22ec53510dd511c/packages/font-icons-mdl2/src/index.ts#L31-L57

Uses in Stylesheet and thus what consuming teams would need if they want to grab a config and align:

https://github.com/microsoft/fluentui/blob/a40470aff64a92bae7bb560bfd69192405001b9e/packages/merge-styles/src/Stylesheet.ts#L97-L103

Results in this error:
TS2717: Subsequent property declarations must have the same type. Property 'FabricConfig' must be of type '{ fontBaseUrl?: string | undefined; iconBaseUrl?: string | undefined; } | undefined', but here has type '{ mergeStyles?: IStyleSheetConfig | undefined; } | undefined'.

Expected Behavior

FabricConfig uses IFabricConfig and all places within FluentUI React are aligned.

Logs

No response

Requested priority

Normal

Products/sites affected

MADS

Are you willing to submit a PR to fix?

yes

Validations

• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• The provided reproduction is a minimal reproducible example of the bug.