fix(effects): add support for Proxy objects in Effects

[MortenGregersen]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/ngrx/platform/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Right now mergeEffects fails with an error when a Proxy object is injected in an Effects class.

Closes #2975

What is the new behavior?

With this extra condition Proxy will be filtered out.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

I don't fully understand how the commit message should be formed and if there should be any documentation changes. I hope you can help with that.

[ngrxbot]

Preview docs changes for 62030b5 at https://previews.ngrx.io/pr2976-62030b5a/

[timdeschryver]

LGTM, I just would like to add a comment on why the extra check is needed, because this is an edge case.

A bit out of scope but do you have an example of a capacitor plugin that is used as an Effect?

[MortenGregersen]

LGTM, I just would like to add a comment on why the extra check is needed, because this is an edge case.

I've added a comment 👍🏻

A bit out of scope but do you have an example of a capacitor plugin that is used as an Effect?

I don't have a public example using a Capacitor plugin. But the reproduction code for the related issue has an example of the use case we want to fix with this pull request. The Proxy object behaves the same way as Capacitor's plugins.
https://github.com/MortenGregersen/ngrx-proxy/blob/main/src/app/app.module.ts

I have created a related issue on Capacitor's repository, as I think they also should look into this.
ionic-team/capacitor#4356