fix: make metadataHash optional in proposal alnd DAO types

[josemarinas]

Description

Please include a summary of the change and be sure you follow the contributions rules we do provide here

Task ID: OS-XXX

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I ran all tests with success and extended them when possible.
• I have updated the CHANGELOG.md file in the root folder of the package after the [UPCOMING] title and before the latest version.
• I have tested my code on the test network.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[thekidnamedkd]

LGTM! :)