Fix: remove unnecessary error message when selecting the initial goal while creating a new campaign

[glaubersilva]

Resolves GIVE-1339

Description

This PR removes the unnecessary validation and sets the goal input, in the same way, using the settings tab from the campaigns details page.

Affects

The creation of new campaigns.

Visuals

Testing Instructions

1. In the modal for creating a new campaign select the "Amount raised" goal type option first;
2. Select any other option after the previous step;
3. Repeat the step #1;
4. Fill the input with the goal;
5. Click on the “Continue” button;
6. No error should be thrown next to the input.

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

[alaca]

Looks good 👍