Slate latest tutorial update

[chenyixuan625]

Upgrade slate to 2.8.0 to fix the broken TOC. slate_latest is a branch that contains all slate codes of version 2.8.0. And slate_latest_tutorial_update checkout from slate_latest and then cherry-pick all the commits from the current main branch.

Verification: After we replace the main with slate_latest_tutorial_update branch and publish the tutorial. The tutorial should load as expected and its table of contents shows up. Like this:

[shriniketsarkar]

After adding in the cerner-smart-embeddable-lib 1.4.0 version we should add a Verification step for someone to go try out the tutorial to ensure it works as expected.

[chenyixuan625]

After adding in the cerner-smart-embeddable-lib 1.4.0 version we should add a Verification step for someone to go try out the tutorial to ensure it works as expected.

yea, I could try to add in the cerner-smart-embeddable-lib 1.4.0 version changes in my forked repo https://github.com/chenyixuan625/smart-on-fhir-tutorial and see if it works as expected. Since the cerner tutorial's github page is built by this main branch, I didn't come up with a good way to verify before we merge this PR and replace the main with slate_latest_tutorial_update branch Any suggestions or ideas?

[chenyixuan625]

Updated the tutorial to use the latest cerner-smart-embeddable-lib(1.4.0). After this PR is merged and the main branch is updated, a specific PR to update gh-pages branch using the latest cerner-smart-embeddable-lib will be pushed out.