feat: add env var to configure announcement modal button text

[halfwhole]

Problem

The button text on the announcement modal is fixed to "Try me now", but we want it to be configurable

Solution

Add a new env var ANNOUNCEMENT_BUTTON_TEXT that allows configuration of the announcement modal's button text. If not set, the button's text will default back to "Try me now".

Also changed width to minWidth on the button styling, since the button text could overshoot the width limit and be wrapped across multiple lines, which we probably don't want?

Before & After Screenshots

BEFORE:

AFTER:

Tests

• Test it on staging, after adding ANNOUNCEMENT_BUTTON_TEXT

Deploy Notes

New environment variables:

• ANNOUNCEMENT_BUTTON_TEXT (optional): button text on the announcement modal

[thanhdatle]

LGTM!