Accept only string for signing

[mmv08]

• Accepting bytes (Uint8Array) makes it very complicated because it's not well supported on the interface side via web3.js
• use ethers hashMessage function that generates eip-191 compliant hash

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🦋 Changeset detected

Latest commit: 68b6b7f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@gnosis.pm/safe-apps-sdk	Patch
@gnosis.pm/safe-apps-provider	Patch
@gnosis.pm/safe-apps-react-sdk	Patch
@gnosis.pm/safe-apps-web3-react	Patch
@gnosis.pm/safe-apps-web3modal	Patch

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ESLint Summary View Full Report

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Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	5	N/A

• Result: ✅ success
• Annotations: 0 total

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^{Report generated by eslint-plus-action}