Hot Fix: prevent PHP 8+ fatal errors when Tributes add-on is enabled

[glaubersilva]

Resolves GIVE-1306

Description

The problem was happening on PHP 8+ because the ltrim() method on those versions is more restrictive about which type of parameter is accepted. In previous versions, not-string values only threw wanings but in PHP 8+ version it threw a fatal error that prevented the donation workflow.

So, the solution was to prevent the use of values different from a string on the ltrim() method.

Affects

Option-based forms with the Tributes add-on enabled.

Testing Instructions

1. Create a v2 form and enable Tributes;
2. Make a donation but do not opt-in for Tributes;
3. The donation should be finished without fatal errors.

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

[jonwaldstein]

Looks good to me, thanks!

[rickalday]

Passed manual QA tests