Fix Image URL Localization URI

[shimotmk]

I fixed the image URI path as per this issue.

fix #714

[matiasbenedetto]

This seems to work fine; it could be merged. However, I found some issues (not strictly related to this change) when creating child themes and bundling images. For example, If I added an image in a child theme and when creating the child theme, the image was bundled in the parent theme, that would need to be fixed, too.

[madhusudhand]

It is failing in the following scenario.

Steps:

1. Active a block theme such as remote and create a child theme.
2. Now add an image to the child theme, and save.
3. Now save changes to theme by selecting Save Template Changes, Localize Text, Localize Images.
4. Observe that the template localizes the image with get_template_directory_uri()
5. But the image fails to load in the editor.

[shimotmk]

@madhusudhand
Thank you for your comment. I was able to reproduce the problem. I was able to solve it by setting a condition with is_child_theme.

[madhusudhand]

@shimotmk Thanks for addressing the feedback.
Changes looks good to me! 🚀

[vcanales]

@matiasbenedetto For example, If I added an image in a child theme and when creating the child theme, the image was bundled in the parent theme, that would need to be fixed, too.

I think we can address that situation after this fix is merged.