refactor(ui5-list): renamed busy, busyDelay to loading, loadingDelay

[plamenivanov91]

Renames the busy, busyDelay property of the ui5-list to loading and loadingDelay.

BREAKING CHANGE: The busy property of the ui5-list is renamed.
If you have previously used the busy, busyDelay properties:

<ui5-list busy busy-delay="500"></ui5-list>

now you must use loading and loadingDelay properties:

<ui5-list loading loading-delay="500"></ui5-list>

Related: #8461 #7887

[ilhan007]

There is some usage in the new samples that needs to be adjusted as well:

[plamenivanov91]

There is some usage in the new samples that needs to be adjusted as well:

Thanks, I completely forgot the new samples. May be it's a good idea to include them in some of the existing builds or create a new one.

[ilhan007]

There is some usage in the new samples that needs to be adjusted as well:

Thanks, I completely forgot the new samples. May be it's a good idea to include them in some of the existing builds or create a new one.

Unfortunately sample.html is html file even non-existing attributes won't throw errors, for the js files, maybe we can rework them to .ts in future.