fix: align all Popovers to header

[iamacook]

What it solves

Resolves non-uniform alignments

How this PR fixes it

All Popovers in the header now aligned directly below the header.

How to test it

Open the notification, WC, account centre and network switcher popovers and observe them aligned below the header.

Screenshots

Checklist

• I've tested the branch on mobile 📱
• I've documented how it affects the analytics (if at all) 📊
• I've written a unit/e2e test for it (if applicable) 🧑‍💻

[github-actions]

Branch preview

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https://popover_alignment--walletweb.review-wallet-web.5afe.dev

[github-actions]

ESLint Summary View Full Report

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Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

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