💡 Add Support for Third-Party Submission of Governance Actions

### Area

Proposal Pillar

### Is there new design needed?

Yes

### What?

Introduce an option for a **third party** (sponsor) to submit a **proposal** as a **Governance Action** for voting **on behalf of the proposer**.

This feature aims to reduce the **100k ADA deposit** barrier for proposers who lack sufficient funds, improving **fairness** and **inclusivity** while still maintaining safeguards against spam.

Need to consider HWW support for submitting GA transaction.

### Why?

- The **100k ADA deposit** can be a significant barrier for many community members, limiting participation.
- Allowing a **sponsor** to cover the deposit ensures more inclusive participation while still preventing spam proposals.
- Increases flexibility by enabling collaboration between proposers and sponsors.
- Encourages community involvement by empowering those with resources to support valuable proposals.

### How?

- Add an option for a **third-party sponsor** to claim responsibility for the **deposit submission**.
- Implement a **two-step approval process** to ensure security and mutual agreement:
- The **proposer** must **approve** the sponsor's intent to submit the proposal.
- The **sponsor** must **confirm** and **sign the transaction** to complete submission.
- Include clear **UI indicators** for proposals that can be claimed for sponsorship approval.
- Ensure appropriate **transaction metadata** to link both parties to the submitted Governance Action.

### (Optional) User Story with acceptance criteria

- [ ] A **"Submit on Behalf"** option is available when creating a Governance Action.
- [ ] Proposers can review and **approve sponsorship requests**.
- [ ] Sponsors must **confirm and sign** the transaction to complete submission.
- [ ] Successfully submitted Governance Actions display both the **proposer's name** and the **sponsor's name** in the details.
- [ ] UI clearly indicates when a proposal is **awaiting sponsorship approval**.