IFrame navigation fail when running under low IL

Associated with https://github.com/MicrosoftEdge/WebView2Feedback/issues/198.

I'm experiencing problems with IFrame elements when attempting to use the WebView2 component from a security sandboxed application running under low integrity level (low IL).

Steps to reproduce:

• Build WebView2APISample from https://github.com/MicrosoftEdge/WebView2Samples in debug x64 (tested at latest 0b7797b3ce0646160a0edff0075bb471498b2b0c commit at master)
• Run icacls WebView2APISample.exe /setintegritylevel Low so that it will run in low IL.
• Run WebView2APISample.exe --userdirectoryfolder=%LOCALAPPDATA%Low\Temp
• Navigate to https://www.w3schools.com/tags/tag_iframe.ASP
• Press "Try it Yourself" button
• Observe that new window opens and the following error dialog is shown multiple times:

Navigation Failure
---------------------------
IFrame navigation failed: COREWEBVIEW2_WEB_ERROR_STATUS_CONNECTION_ABORTED

Process Explorer can be used to check if a process runs under the low, medium or high IL.

Version
SDK: Microsoft.Web.WebView2 1.0.1056-prerelease
Runtime: Microsoft Edge WebView2 Runtime 96.0.1054.34
Framework: WebView2APISample sample project (build using VS2019)
OS: Windows 10 19043.1348 (x64)

AB#37199076

Start by reproducing the failure in the WebView2APISample project using the low-integrity icacls command, the specified user directory, and the w3schools iframe page. Compare the observed navigation error with the linked WebView2Feedback issue; done would require resolving or clearly identifying the cause of iframe navigation failure under low IL.