Backport use of thread delay over sleep and handle dispose in FileSystemMainDomLock

[AndyButland]

Prerequisites

• I have added steps to test this contribution in the description below

Description

This backports the changes applied in PRs #18119 and #18147.

Test steps are described in the second linked PR. I've verified these on this PR for Umbraco 13.

[nul800sebastiaan]

@AndyButland I've marked the related PRs for release 13.7.0, which is where I think it will go?

[AndyButland]

@JasonElkin - do you think you'd have time to look over this one please, just as a second pair of eyes that I've backported your amend to 13 correctly? Thanks if so.

[JasonElkin]

Umbraco-CMS/src/Umbraco.Infrastructure/Runtime/FileSystemMainDomLock.cs

Lines 148 to 149 in e5a1398

	_lockFileStream?.Close();
	_lockFileStream = null;

Should be replaced by a call to ReleaseLock()

[AndyButland]

Thanks @JasonElkin, have updated. I'll include this in the 13.7 release candidate due out today.

Have applied changes.