Fix: CSS in modal header

[katspaugh]

What it solves

Resolves #3288

How this PR fixes it

Adds nowrap to the modal header and and overflow: hidden to the ChainIndicator

Screenshots

When there's not enough space, the ChainIndicator will be cut off:

[github-actions]

CLA Assistant Lite All Contributors have signed the CLA.

[github-actions]

ESLint Summary View Full Report

Annotations are provided inline on the Files Changed tab. You can also see all annotations that were generated on the annotations page.

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

• Result: ✅ success
• Annotations: 0 total

---

^{Report generated by eslint-plus-action}

[iamacook]

LGTM! 🔥

[github-actions]

Deployment links

🟠 Safe Rinkeby	⚪ Safe Mainnet	🟣 Safe Polygon	🟡 Safe BSC	⚫ Safe Arbitrum	🟢 Safe xDai

[coveralls]

Pull Request Test Coverage Report for Build 1683504875

• 1 of 2 (50.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.002%) to 32.422%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/components/Modal/index.tsx	1	2	50.0%

Totals
Change from base Build 1682592319:	0.002%
Covered Lines:	3112
Relevant Lines:	8549

---

💛 - Coveralls

[github-actions]

E2E Tests Failed
Check the results here: https://github.com/gnosis/safe-react-e2e-tests/actions/runs/1683545516

Failed tests:

• ❌ Safe Apps List Safe Apps List

[francovenica]

This fixes the issue of the X fine, but I'm not sure about just cutting the chain name.
I'll be ok closing this as resolved, but I'd create a ticket for the designer to think of a way to put the full name of the network
cc @johannesmoormann