Fix YAML frontmatter in two skills

[LiorLivyatan]

What changed

• Format the sumsub-create-workflow description as a folded YAML scalar.
• Format the sumsub-theme-msdk description as a folded YAML scalar.

Why

Both descriptions contain an unquoted colon followed by a space:

• live traffic: in sumsub-create-workflow
• SumsubTheme: SNSTheme in sumsub-theme-msdk

YAML parses those as mapping separators, so skill installers reject both
manifests with mapping values are not allowed here.

This change preserves the description text and only makes its YAML
representation valid.

Validation

Before the change, Codex's skill validator reproduced the YAML parsing error
for both skills. After the change:

Skill is valid!
Skill is valid!

Both corrected skills were also installed successfully with the skills CLI
and validated again from their installed locations.