fix: conflicting ts field type

[tiagoapolo]

Fix ts class field conflicting type definitions

This was causing issues when defining flagsmith.json type to IState as reported in #292

[Copilot]

PR Overview

This pull request aims to resolve conflicting type definitions for the ts field in the Flagsmith class, addressing issues with the flagsmith.json type.

• Updated the ts field from "number | null = null" to an optional "ts?: number".
• Removes the default null assignment to adhere to type definitions expected by IState.

Reviewed Changes

File	Description
flagsmith-core.ts	Changed ts field type to an optional number to fix type conflicts.

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

flagsmith-core.ts:264

• Changing 'ts' from a field initialized to null to an optional number means it may be undefined in some cases. Please verify that all usages of 'ts' properly handle undefined values to maintain consistent behavior.

ts?: number