Update ERC-2678: remove duplicate words in ERC-2678, ERC-3589, ERC-5553, ERC-5570

[0xAxiom]

Removes duplicate-word typos found via grep across the ERCS/ tree.

• ERC-2678 (line 950): `A deployed instance of the `Wallet` contract would be of of type` → `would be of type`
• ERC-3589 (line 73): `a collector has hundreds of of NFTs` → `hundreds of NFTs`; `They all need a way a assemble those NFTs together` → `a way to assemble those NFTs together`
• ERC-5553 (line 108): `a license payment formula can be created so that that` → `so that`
• ERC-5570 (line 39): `the digital receipt specified in in the JSON schema below` → `specified in the JSON schema below`

All changes are non-substantive editorial fixes — no semantics modified.

Commit is GPG-signed.

[eip-review-bot]

File ERCS/erc-2678.md

Requires 1 more reviewers from @chriseth, @fubuloubu, @gnidan, @iamdefinitelyahuman, @njgheorghita, @pipermerriam
Requires 2 more reviewers from @g11tech, @jochem-brouwer, @lightclient, @samwilsn, @xinbenlv

File ERCS/erc-3589.md

Requires 1 more reviewers from @Ungigdu, @xinqiyang
Requires 1 more reviewers from @g11tech, @jochem-brouwer, @samwilsn, @xinbenlv

File ERCS/erc-5553.md

Requires 1 more reviewers from @royosherove
Requires 1 more reviewers from @g11tech, @jochem-brouwer, @samwilsn, @xinbenlv

File ERCS/erc-5570.md

Requires 1 more reviewers from @darcys22
Requires 2 more reviewers from @g11tech, @jochem-brouwer, @lightclient, @samwilsn, @xinbenlv

[github-actions]

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