chore: Move the cookie prompt to the bottom

[davidfcopozo]

Move cookie prompt to the bottom #341

Changes made

• Positioned the metrics notification to the bottom as intended
• Change notification wrapper width units from absolute to relative, which helps with responsiveness consistency
• Remove the auto margin since justifying the content to the center takes care of centering the content
• Added a z-index of 1 since the body's content was overlapping the metrics notifications

Before the changes:

After the changes:

[SgtPooki]

@davidfcopozo thanks for putting this together but we've got @djmcquillan taking care of this. Follow #340 for more info. Also see #359 and #358