Change the scope of BmpCheckPlugin to global (#1499)

## Description

Change the scope of BmpCheckPlugin to global. 
Requiring platforms to include the 'surfacefamily' scope in order to use
this plug-in is unreasonable.

- [ ] Impacts functionality?
- [ ] Impacts security?
- [x] Breaking change?
- [ ] Includes tests?
- [ ] Includes documentation?
- [x] Backport to release branch?

## How This Was Tested

Verified that BmpCheckPlugin will be loaded by include scope "global".

## Integration Instructions
This will enable a new post build plugin, where it was previously only
scoped to surfacefamily.

If this plugin breaks in a project, it means that the BMP file the
project is using is either malformed or that it contains excessive data
that is not part of the BMP. Close examination of the BMP is recommend,
or regeneration of the BMP.

Co-authored-by: PO-HAN CHEN <[email protected]>

Author: pohancn

BaseTools/Plugin/BmpCheck/BmpCheck_plug_in.json

@@ -1,5 +1,5 @@
 {
-  "scope": "surfacefamily",
+  "scope": "global",
   "name": "Bmp Image Encoding Check",
   "module": "BmpCheckPlugin"
 }