Display upgrade verification prompt

[Anderas]

Related SDK change matrix-org/matrix-ios-sdk#1751

Resolves https://github.com/vector-im/crypto-internal/issues/58

Display customized modal alert if upgrading from legacy to rust crypto and needing to verify the account.

[BillCarsonFr]

LGTM

[pixlwave]

I'm not sure I fully understand how this works - I don't see where showVerificationUpgradeAlert gets set back to true and when it would get set back to false after an alert. But the code looks fine to me.

[pixlwave]

I think this would be more inline with the project's style:

Suggested change

	if
	let feature = MXSDKOptions.sharedInstance().cryptoSDKFeature,
	feature.isEnabled && feature.needsVerificationUpgrade
	{
	if let feature = MXSDKOptions.sharedInstance().cryptoSDKFeature,
	feature.isEnabled && feature.needsVerificationUpgrade {

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (hotfix/1.10.7@022d7e7). Click here to learn what that means.
Patch has no changes to coverable lines.

❗ Current head bff0b28 differs from pull request most recent head 8202617. Consider uploading reports for the commit 8202617 to get more accurate results

Additional details and impacted files

@@               Coverage Diff                @@
##             hotfix/1.10.7    #7454   +/-   ##
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  Misses                   ?   142280           
  Partials                 ?      649           

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[Anderas]

I'm not sure I fully understand how this works - I don't see where showVerificationUpgradeAlert gets set back to true and when it would get set back to false after an alert. But the code looks fine to me.

Discussed the mechanism offline