fix(slider): Step with esriImage

[jolevesq]

Closes #2574

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Add a stepper select box for single handle discrete dimension. In RAMP we had 2 handle for esriImage so user was able to set dimension. Now it is single handle, it is why we need this selector.

Fixes #2574

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.

Hosted November 4th, 9am

https://jolevesq.github.io/geoview/demos-navigator.html?config=./configs/navigator/10-package-time-slider.json

Go to time slider, then see how we can change step for the first layer who is a esriImage.

We do not deal properly with esriImage, this PR is patch to behave like RAMP but further work will be needed #2576

Checklist:

• I have build (rush build) and deploy (rush host) my PR
• I have connected the issues(s) to this PR
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have created new issue(s) related to the outcome of this PR is needed
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

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This change is 

[Alex-NRCan]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @DamonU2)

[DamonU2]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jolevesq)