fix: Fix tax on donation tickets

[mrsaicharan1]

Screenshot

22% tax rate (separate fee on top of price)

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Fixes #3259

Short description of what this resolves:

Resolves the issue with the resultant negative tax popping up due to the non-updation of the ticket price in the computed property

Changes proposed in this pull request:

• Added price as a watchable property to update the computed property

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the Upstream development branch.
• The acceptance, integration, unit tests and linter pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)