supportUntrustedWorkspaces override is ignored for source control providers

[joepie91]

Issue Type: Bug

1. Open untrusted workspace
2. See an error in the source control pane: "None of the registered source control providers work in Restricted Mode"
3. Observe that vscode.git has been disabled in untrusted workspaces in a recent update
4. Attempt to re-enable it by adding an override for it to extensions.supportUntrustedWorkspaces in settings.json
5. Observe that, after a reload, the extension is indeed re-enabled under the built-in extensions, but...
6. ... the source control pane still shows the same error, instead of the actual Git integration

From a glance at the implementation for this error condition, the error seems to be always shown when the editor is in Restricted Mode, regardless of whether any source control providers have actually indicated support for this mode.

VS Code version: Code 1.63.1 (fe719cd, 2021-12-14T02:02:02.183Z)
OS version: Linux x64 5.14.21
Restricted Mode: Yes

System Info

Item	Value
CPUs	AMD Ryzen 9 3900X 12-Core Processor (24 x 2200)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off opengl: enabled_on rasterization: disabled_software skia_renderer: enabled_on video_decode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	62.76GB (2.78GB free)
Process Argv
Screen Reader	no
VM	0%
DESKTOP_SESSION	plasma5
XDG_CURRENT_DESKTOP	KDE
XDG_SESSION_DESKTOP	plasma5
XDG_SESSION_TYPE	x11

Extensions (14)

Extension	Author (truncated)	Version
Bookmarks	ale	13.2.2
Nix	bbe	1.0.1
language-postcss	cpy	1.1.0
flow-for-vscode	flo	1.9.2
beautify	Hoo	1.5.0
l13-diff	L13	1.0.3
python	ms-	2021.12.1559732655
vscode-pylance	ms-	2021.12.2
jupyter	ms-	2021.11.1001550889
jupyter-keymap	ms-	1.0.0
vscode-quick-open-create	noc	0.6.0
mdx	sil	0.1.0
rewrap	stk	1.15.4
debug	web	0.25.1

(9 theme extensions excluded)

[lszomoru]

To verify:

1. Add the following into your settings.json:

    "extensions.supportUntrustedWorkspaces": {
        "vscode.git": {
            "supported": true
        }
    },

2. Open a workspace containing a git repository and choose to stay in restricted.
3. Confirm that the SCM viewlet is rendered as expected and no welcome messages are shown