No information that a safe can not be used as a proposer

[liliya-soroka]

##Description
No information that a safe can not be used as a proposer

Environment

• Browser: Chrome
• Wallet: any
• Chain: any

Steps to reproduce

1. Go to the proposers in the settings

2. try to add a safe as a proposer
   Current result: the safe as a proposer added

3. try to propose a tx as a safe-proposer
   Current result: The propose is failing

Expected result

If the safe-proposer can not propose a tx we should have a validation and information on the add proposer step

Obtained result

Screenshots