[EuiIcon] Remove size 's' (12px)

[ryankeairns]

Teams working on Discover have received feedback that some icons are too small. Namely, the actions in Discover's data grid table. This has evolved into a larger question whether s (12px) sized icons are too small in general and should be removed as an option on EuiIcon.

Impact

Supposing we were aligned on removing this size, what would be the impact to the largest consumers?

Kibana
On a quick scan with this regrex <EuiIcon[ \w=\{\}>\(\)\n;".-:]* size="s",
I see just over 200 instances of <EuiIcon ... size=-"s"...

EUI
Small size icons are not simply for bespoke use. They are used in other EUI components such as...

• data grid toolbar
• pagination
• links (external)
• tree view (compressed)
• form controls (compressed prepend/addend?)

Alternatives

1. Deprecate the s size and adapt impacted EUI components
2. Deprecate the s size for EuiIcon but somehow keep the size in play for EUI components (so they don't have to be updated)
3. Keep it but create stricter guidelines on its usage and instruct downstream teams to move away from nonconforming usage (increase the size used for data grid actions?)
4. Other?