fix: correct base64 data URI segment count validation in readImage

[msluszniak]

Description

A base64 data URI (e.g. data:image/png;base64,iVBOR...) splits text into 2 segments, but the check was comparing against 1, causing all valid base64 image inputs to be rejected.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

Run tests and check if they work.

Screenshots

Related issues

#809

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes