fix: Prevent html injection in ProfileForm

[ciurana-life]

Description

• Fix for #537
• Blocks special characters in the browser for "full name" input
• Blocks special characters with backend validation for "full name"

HTML pattern attribute explanation here.

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[mairasalazar]

LGTM!

[slint]

LGTM, one minor thing about using the wtforms API differently for the validation