can't sign

Type: Bug

i can't login for acount git, and me can't use copilot github

Extension version: 0.27.1
VS Code version: Code 1.100.2 (848b80aeb52026648a8ff9f7c45a9b0a80641e2e, 2025-05-14T21:47:40.416Z)
OS version: Windows_NT x64 10.0.26100
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|12th Gen Intel(R) Core(TM) i5-1240P (16 x 2112)|
|GPU Status|2d_canvas: enabled
canvas_oop_rasterization: enabled_on
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: disabled_off
video_decode: enabled
video_encode: enabled
vulkan: disabled_off
webgl: enabled
webgl2: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|undefined|
|Memory (System)|7.71GB (1.63GB free)|
|Process Argv|--crash-reporter-id 88b4e900-20ff-4d44-a2d1-feba1d3fef5c|
|Screen Reader|no|
|VM|0%|

A/B Experiments

```
vsliv368cf:30146710
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscod805cf:30301675
binariesv615:30325510
c4g48928:30535728
azure-dev_surveyone:30548225
a9j8j154:30646983
962ge761:30959799
2e7ec940:31000449
pythontbext0:30879054
cppperfnew:31000557
dwnewjupyter:31046869
pythonrstrctxt:31112756
nativeloc1:31192215
5fd0e150:31155592
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
customenabled:31248079
9064b325:31222308
copilot_t_ci:31222730
e5gg6876:31282496
pythoneinst12:31285622
bgtreat:31268568
4gafe986:31271826
c7cif404:31314491
996jf627:31283433
pythonrdcb7cf:31303019
usemplatestapi:31297334
0aa6g176:31307128
7bj51361:31289155
747dc170:31275177
pylancecolor:31314202
aj953862:31281341
generatesymbolt:31295002
convertfstringf:31295003
gendocf:31295004
i845d553:31303030

```

No file, test, error message, or reproduction steps are provided. Start by reproducing the GitHub sign-in failure in VS Code with extension version 0.27.1 on Windows, then trace the extension's authentication entry point and inspect relevant logs; done means identifying and verifying a fix for login and Copilot access.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.