[Security Solution][EUI visual refresh] change usages of `success` to `textAccentSecondary`

[PhilippeOberti]

Context

Changes are made to EUI that will be visible to end-users in Kibana:

• Updated all colors in EUI
• Reduce the topmost font weights and sizes (think titles and headings) These changes are available in a new theme called Borealis.

See parent ticket for how to use the new theme and labels to add to the PR for tracking

Description

All usages of "successText" colors have been updated to "textAccentSecondary" as needed.

[!IMPORTANT] Please following the same guide provided for the success color above to update successText to textAccentSecondary where needed.

# previous color token -> new color token
successText -> textSuccess
successText -> textAccentSecondary // This is new, follow the same instructions above for the "success" color to determine usage 

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[elasticmachine]

Pinging @elastic/security-threat-hunting (Team:Threat Hunting)

[elasticmachine]

Pinging @elastic/security-threat-hunting-investigations (Team:Threat Hunting:Investigations)