Update Subtitle to Support h2-h6 Tags

[SpaNb4]

📝 Describe the feature

Subtitle component currently only renders an h3 tag.
The component should accept a new prop, for example, headingLevel (or similar, such as as), which is a string specifying the heading tag to be rendered. The component will default to h3 if this prop is not provided.

✅ Definition of Done (DoD):

• New headingLevel Prop: The Subtitle component accepts a new prop named headingLevel (or as if preferable) as a string to specify the heading tag to be rendered. Valid values are h2, h3, h4, h5, and h6.
• Default h3: If the headingLevel prop is not provided, the component should default to rendering an h3 tag.
• Refactoring: All existing instances of the Subtitle component in the codebase have been reviewed and refactored to use the headingLevel prop where necessary and maintain all the existing styling.
• Unit tests: New unit tests should be added to ensure that the new headingLevel prop behaves as expected with different heading levels.
• No Styling Breaks: The current style of the subtitles doesn't break on any usage

[ansivgit]

Also we would like variants for font-weight for it