Fix issue when adding image when no blocks are present

[planarvoid]

Fix

There is an issue that when there are no blocks in the selection and the user wants to add an image. In that case the selection is set to 0 and the image is added to the beginning of the editor.

I've added unit tests to cover this functionality as well

Test

1. Turn on aztec.visualEditor.addMediaAfterBlocks() in the MainActivity
2. Set EXAMPLE to something like <h1>Test 1</h1>\nBody
3. Run the app
4. Click at the end of Body
5. Add an image
6. Check it gets added after the Body and not at the beginning of the editor

Review

@AmandaRiu

Make sure strings will be translated:

• If there are new strings that have to be translated, I have added them to the client's strings.xml as a part of the integration PR.

[AmandaRiu]

@planarvoid One thing I did notice is that if nothing is selected then the image is added to the end of the last block span detected which seems fine until you have regular text following the block. For example, if I set the EXAMPLE text to "<h1>Test 1</h1>\nMy Test", then run the app and just tap to add a photo (without tapping inside the editor so selectionEnd is 0), then the image is added between the Heading and the body. This is an edge case I realize and I'm not sure what the fix would be in that case other than either defaulting the position to either 0 to add the image to the top of the document, or to editableText.length to return the position at the end of the document. I think the second option would keep everything in line with expected functionality for Aztec, but either way I'm not sure it's a big enough problem to address in this PR.

I also added a code comment for your review. Everything works great so approved, but will wait to merge in case you are still online to look at this real quick.

[planarvoid]

thanks for the review @AmandaRiu

One thing I did notice is that if nothing is selected then the image is added to the end of the last block span detected which seems fine until you have regular text following the block. For example, if I set the EXAMPLE text to "

Test 1

\nMy Test", then run the app and just tap to add a photo (without tapping inside the editor so selectionEnd is 0), then the image is added between the Heading and the body. This is an edge case I realize and I'm not sure what the fix would be in that case other than either defaulting the position to either 0 to add the image to the top of the document, or to editableText.length to return the position at the end of the document. I think the second option would keep everything in line with expected functionality for Aztec, but either way I'm not sure it's a big enough problem to address in this PR.

Good catch 👍 , I've added an edgecase solution just for this usecase (if selection start and end are 0, insert at the beginning of the entry).

[AmandaRiu]

Changes look good! I'll merge as soon as CI has passed 👍🏻