Make custom image location regex match return correct full URL

[DaoDaoNoCode]

Closes #1641

Description

It's because the image regex is returning the full match result as the URL but not the full URL, so the tag is omitted.

How Has This Been Tested?

Follow the same way in the issue description:

1. Go to Notebook image settings
2. Try to import an image using SHA256-encoded tag like quay.io/opendatahub/workbench-images@sha256:b6532b34c9bf0710ecbd76407c8909742914bdacd17add3e04ab49e7c81a2800
3. Make sure the image can be successfully imported and the image location is shown correctly

Test Impact

N/A

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• Commits have been squashed into descriptive, self-contained units of work (e.g. 'WIP' and 'Implements feedback' style messages have been removed)
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has added tests or explained why testing cannot be added (unit tests & storybook for related changes)

If you have UI changes:

• Included any necessary screenshots or gifs if it was a UI change.
• Included tags to the UX team if it was a UI/UX change.

After the PR is posted & before it merges:

• The developer has tested their solution on a cluster by using the image produced by the PR to main

[lucferbux]

/lgtm

[alexcreasy]

@DaoDaoNoCode have you built this and tested it on a cluster?

[DaoDaoNoCode]

@alexcreasy yes, I did that the last moment before my demo started :P

[alexcreasy]

Built an image and tested on my cluster, works great!

[alexcreasy]

@alexcreasy yes, I did that the last moment before my demo started :P

Then pls tick the box from the template :)

[alexcreasy]

/approved

[DaoDaoNoCode]

@alexcreasy Ah because it's not going to main, it's going to incubation

[alexcreasy]

@alexcreasy Ah because it's not going to main, it's going to incubation

@DaoDaoNoCode yeah, good point, I'll create a new template for going to incubation tomorrow morning my time!

[openshift-ci]

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