Fix: replace Button with anchor tag in EntityAnnotation toggle

[garvthakre]

Problem

Related ticket: BB-869
This ticket has two issues:

1.Long annotations getting cut halfway through ,this is already fixed on the live site and locally.
2.The "Show more/less" toggle using a Bootstrap Button component ,this is still unfixed.

Solution

1.Replaced the Bootstrap Button component with a plain tag with role="button" for better semantics and accessibility.
2.Added e.preventDefault() to prevent the default anchor scroll behavior.
3.Removed the now-unused Button import.

Areas of Impact

src/client/components/pages/entities/annotation.js

[garvthakre]

Hey @MonkeyDo, could you take a look when you get a chance? It's a small change ,just replacing a Bootstrap Button with a plain tag in the annotation toggle. Should be a quick review!