Fix for snapshot dismissal

[bbirman]

In #3679 I changed the notification we use to dismiss snapshot from UISceneDidActivateNotification to UISceneWillEnterForegroundNotification because UISceneDidActivateNotification isn't called for screen mirroring and I thought UISceneWillEnterForegroundNotification could cover both cases. There's a new issue with using UISceneWillEnterForegroundNotification so this PR separates it into using UISceneDidActivateNotification for the main flow like it was originally and UISceneWillEnterForegroundNotification for the non-interactive/mirrored case

[bbirman]

Added this to check the object on the notification more safely

[github-actions]

	1 Warning
⚠️	Static Analysis found an issue with one or more files you modified. Please fix the issue(s).

Clang Static Analysis Issues

File	Type	Category	Description	Line	Col
SalesforceSDKManager	Nil value used as mutex for @synchronized() (no synchronization will occur)	Logic error	Nil value used as mutex for @synchronized() (no synchronization will occur)	147	5
SalesforceSDKManager	Nil value used as mutex for @synchronized() (no synchronization will occur)	Logic error	Nil value used as mutex for @synchronized() (no synchronization will occur)	159	5

Generated by 🚫 Danger

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 33.33333% with 22 lines in your changes missing coverage. Please review.

Project coverage is 63.13%. Comparing base (8347820) to head (32fa134).

Files with missing lines	Patch %	Lines
...forceSDKCore/Classes/Common/SalesforceSDKManager.m	33.33%	22 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #3778      +/-   ##
==========================================
- Coverage   63.35%   63.13%   -0.22%     
==========================================
  Files         227      227              
  Lines       21590    21736     +146     
==========================================
+ Hits        13678    13723      +45     
- Misses       7912     8013     +101     

Components	Coverage Δ
Analytics	84.09% <ø> (ø)
Common	68.96% <ø> (ø)
Core	52.53% <33.33%> (-0.24%)	⬇️
SmartStore	73.65% <ø> (ø)
MobileSync	87.58% <ø> (ø)

Files with missing lines	Coverage Δ
...forceSDKCore/Classes/Common/SalesforceSDKManager.m	53.12% <33.33%> (-5.62%)	⬇️

... and 3 files with indirect coverage changes

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[bbirman]

Merging because the failing test (testCredentialsCopying) looks like it started flapping before this PR. Looking into it but I haven't been able to repro locally yet