fix(iOS): KV, Context fixes

[theproducer]

This PR fixes various issues on the iOS Engine:

• KV: KV.get on an non-existent key returned an empty object instead of null
• Fixed an issue within Runner that could potentially cause EXC_BAD_ACCESS crashes

[changeset-bot]

🦋 Changeset detected

Latest commit: 7df7a60

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@capacitor/background-runner	Minor
ios-engine	Minor
example-app	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[louis123562]

Sorry if this is not the ideal place for my notes; but i want you to know that with any version > 1.0.5 (e.g. 1.0.6-dev-20240409T144959.0 or 1.0.6-dev-20230915T160000.0) the CPU of the iOS-Device is always under pressure (high load) shortly after starting the app, even without dispatching any event.

Maybe you can have a look at that, too?

I am very excited for a new version :)

[theproducer]

Sorry if this is not the ideal place for my notes; but i want you to know that with any version > 1.0.5 (e.g. 1.0.6-dev-20240409T144959.0 or 1.0.6-dev-20230915T160000.0) the CPU of the iOS-Device is always under pressure (high load) shortly after starting the app, even without dispatching any event.

Maybe you can have a look at that, too?

I am very excited for a new version :)

Hello!

I would open a new issue with a test app that reproduces the issue (and preferably screenshots from Instruments showing CPU load).

If you have general questions, you can ping me in the Ionic Discord.

[markemer]

Like the updates to `throws, LGTM