Fix updating image before initial image is loaded or the loading failed

[maciejmatu]

This PR fixes issue with updating image source immediately after creating the source, or after a failed image request, mentioned in #11725. The only change is removal of condition that disallowed updating image until this.image was instantiated on the ImageSource class.

• briefly describe the changes in this PR
• include before/after visuals or gifs if this PR includes visual changes
• write tests for all new functionality
• document any changes to public APIs
• add an entry inside this element for inclusion in the mapbox-gl-js changelog: <changelog>Allow ImageSource.updateImage to be called before initial image loads or fails to load</changelog>

[stepankuzmin]

Hi @maciejmatu,

Thanks for the contribution! I see one render test is failing continuously. Could you please rebase your PR on top of the main branch?

[maciejmatu]

Thanks @stepankuzmin I've had some troubles, and it kept failing. Should I close this PR?

[stepankuzmin]

Yep, I'll close this PR after we merge the rebased one. Thanks again for the contribution 🙏

[stepankuzmin]

Merged in #12992

[maciejmatu]

Thanks!