Random signing failure in the Windows build

https://github.com/element-hq/element-web/actions/runs/28586487655/job/84759980788

```
• signing failed for file, queue will continue to next file file=dist\win-unpacked\Element.exe error=C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe process failed ERR_ELECTRON_BUILDER_CANNOT_EXECUTE
Exit code:
null
Output:
Exit code: null. Command failed: C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe sign /tr http://timestamp.digicert.com/ /sha1 35BDC586E2284E165170D8938F737E1FFAF695D4 /s My /fd sha256 /td sha256 /d Element /du https://element.io/ /debug D:\a\element-web\element-web\apps\desktop\dist\win-unpacked\Element.exe

The following certificates were considered:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

After EKU filter, 1 certs were left.
After expiry filter, 1 certs were left.
After Hash filter, 1 certs were left.
After Private Key filter, 1 certs were left.
The following certificate was selected:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

Done Adding Additional Store

⨯ C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe process failed ERR_ELECTRON_BUILDER_CANNOT_EXECUTE
Exit code:
null
Output:
Exit code: null. Command failed: C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe sign /tr http://timestamp.digicert.com/ /sha1 35BDC586E2284E165170D8938F737E1FFAF695D4 /s My /fd sha256 /td sha256 /d Element /du https://element.io/ /debug D:\a\element-web\element-web\apps\desktop\dist\win-unpacked\Element.exe

The following certificates were considered:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

After EKU filter, 1 certs were left.
After expiry filter, 1 certs were left.
After Hash filter, 1 certs were left.
After Private Key filter, 1 certs were left.
The following certificate was selected:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

Done Adding Additional Store
failedTask=build stackTrace=Error: C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe process failed ERR_ELECTRON_BUILDER_CANNOT_EXECUTE
Exit code:
null
Output:
Exit code: null. Command failed: C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x86\signtool.exe sign /tr http://timestamp.digicert.com/ /sha1 35BDC586E2284E165170D8938F737E1FFAF695D4 /s My /fd sha256 /td sha256 /d Element /du https://element.io/ /debug D:\a\element-web\element-web\apps\desktop\dist\win-unpacked\Element.exe

The following certificates were considered:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

After EKU filter, 1 certs were left.
After expiry filter, 1 certs were left.
After Hash filter, 1 certs were left.
After Private Key filter, 1 certs were left.
The following certificate was selected:
Issued to: Esigner LLC

Issued by: SSL.com EV Code Signing Intermediate CA RSA R2

Expires: Sun Jul 11 15:45:40 2027

SHA1 hash: 35BDC586E2284E165170D8938F737E1FFAF695D4

Done Adding Additional Store

at D:\a\element-web\element-web\node_modules\.pnpm\builder-util@26.15.3\node_modules\builder-util\src\util.ts:192:18
at ChildProcess.exithandler (node:child_process:424:5)
at ChildProcess.emit (node:events:509:28)
at maybeClose (node:internal/child_process:1124:16)
at Process.ChildProcess._handle.onexit (node:internal/child_process:306:5)

Warning: command "pnpm exec electron-builder --publish never -w squirrel msi" exited with non-zero status code
NX Running target build for project element-desktop and 2 tasks it depends on failed
```

Start with the linked GitHub Actions run and the Windows desktop build command, `pnpm exec electron-builder --publish never -w squirrel msi`. Inspect how `signtool.exe` is invoked for `dist\win-unpacked\Element.exe` and investigate why signing fails intermittently. Done means the Windows build completes successfully with the executable signed.

Written by the indexing model from the issue text.