feat: Fix handlebars template syntax in labels

[najuna-brian]

Description

Fixes handlebars template syntax in labels that was not being expanded. Labels with syntax like {{data.fieldName}} now properly replace placeholders with actual form data values.

Changes

• Added handlebars template processing in HtmlLabelRenderer.tsx
• Uses useJsonForms() hook to access form data reactively
• Processes {{data.fieldName}} syntax to replace with actual values
• Handles missing values gracefully (replaces with empty string)
• Maintains backward compatibility with labels without handlebars syntax

Testing

✅ Tested on phone with p_wealth_new form - handlebars templates now expand correctly

• As shown beow, the missing data just shows nothing before it is entered, then the data and time shows as below on that form

Related Issue

Fixes https://github.com/Omo-Valley-Research-Project/AnthroCollect/issues/34

[Mishael-2584]

Looks good. Could we consider supporting nested paths if needed in the future?