Review technical content: Desktop Wallet shared accounts - transactions

[TinaKT]

Technical review of the multi-signature transaction features under "Shared accounts with multiple credentials in Desktop Wallet" to verify technical accuracy and completeness.

Review focus:

• Correctness of all technical information
• Completeness of information
• Removal of irrelevant or redundant information

Review is complete when:

• All technical information has been verified
• Missing information has been identified and added
• Irrelevant or redundant information has been deleted
• PR with necessary changes has been submitted

Pages to review:

1. Create a multi-signature CCD transfer in the Desktop Wallet: https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/multisig-simple-transfer.rst
2. Create a scheduled transfer in the Desktop Wallet: https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/guides/multisig-transfer.rst
3. Sign a transaction proposal: https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/sign-transaction.rst
4. View transaction proposals: https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/proposed-transactions.rst

Note: A separate review of language and style will be conducted after the technical review is complete.