feat: use global variable to load latest sdk-partitions file from trebuchet

[dayaffe]

Use latest sdk-partitions.json data provided by trebuchet

Issue #

#1652

Description of changes

• Load partitions data from file rather than a static string that is manually updated
• Use of bang (!) is acknowledged in both loading file and String conversion
• By loading contents into a global variable the very first load may take extra time but subsequent loads should use cached version of the partitions json

New/existing dependencies impact assessment, if applicable

Conventional Commits

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