[IOS] There is existed a big empty space between Signature and attachment if user expand / collapse signature before uploading attachment

[QuangHoang1210]

ENV:

• IOS app
• Tmail v0.11.3411

Precondition:

• User already create identity signature
• User uploading attachment after expand signature

Step: 1- User open composer 2- User expand / collapse the signature 3- User upload any attachment

Actual:

• Signature and attachment have a big empty space

Expected:

• Attachment position should be right bellow Signature

https://github.com/linagora/tmail-flutter/assets/124866146/bf0c2af6-7e34-48af-bae4-0dfe862d5b4f