Fix an issue with posts duplicated in Discover

[kean]

Description

Fixes CMM-764: Reader: posts in Discover are duplicated

Testing instructions

I tested by duplicated a post in a mock response.

Before / After

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	29937
	Version	PR #25015
	Bundle ID	org.wordpress.alpha
	Commit	c7f83f9
	Installation URL	7strr9dld655g

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	29937
	Version	PR #25015
	Bundle ID	com.jetpack.alpha
	Commit	c7f83f9
	Installation URL	3sa9lnea2pb2o

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[crazytonyli]

You can update the ReaderPost.createOrReplace signature to declare a nonnull return type, and then the ReaderPost? in findExistingCard(with post: ReaderPost?, ...) can become non-optional ReaderPost.

[kean]

I'd rather keep the changes to the minimum. I'm not completely sure createOrReplace is non-optional. It looks like it is.

The containing function will still return optional for now due to:

guard remoteCard.type != .unknown else {
            return nil
        }

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 26.5 ❄️. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

	1 Message
📖	This PR contains changes to RELEASE-NOTES.txt. Note that these changes won't affect the final version of the release notes as this version is in code freeze. Please, get in touch with a release manager if you want to update the final release notes.

Generated by 🚫 Danger

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud