Refactor FXIOS-9383 - Update Fonts related to Onboarding to use FXFontStyles

[bmihai23]

:scroll: Tickets

Jira ticket Github issue

:bulb: Description

• This PR updates the font styles used in the OnboardingCardViewController class to improve consistency and adaptability to dynamic font sizes.

iPhone 15 Pro - Before

Light Theme	Dark Theme

iPhone 15 Pro - After

Light Theme	Dark Theme

iPhone SE (2nd generation) - Before

Light Theme	Dark Theme

iPhone SE (2nd generation) - After

Light Theme	Dark Theme

iPad Pro (M4) - Before

Portrait	Landscape

iPad Pro (M4) - After

Portrait	Landscape

:pencil: Checklist

You have to check all boxes before merging

• [x] Filled in the above information (tickets numbers and description of your work)
• [x] Updated the PR name to follow our PR naming guidelines
• [ ] Wrote unit tests and/or ensured the tests suite is passing
• [ ] When working on UI, I checked and implemented accessibility (minimum Dynamic Text and VoiceOver)
• [ ] If needed, I updated documentation / comments for complex code and public methods
• [ ] If needed, added a backport comment (example @Mergifyio backport release/v120)