Fix Roadmap timeline bar alignment to match accurately with dates

What does this MR do and why?

Fixes a bug where timeline bars on Roadmap were not aligned correctly to match the dates due to shrunk container element.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Visit a group and create/edit an epic with start and due dates
2. Open Roadmap for the group and verify if timeline bars are aligned in approximation to dates for the epic.
   • Additionally, also try various combinations from Settings sidebar like choosing different daterange and layout options.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #410729 (closed), #393031 (closed)