fix: windows build issue, changed to platform independent external parameter in rollup config file

[Spiral-Memory]

Resolved build problem in windows environment by modifying the rollup configuration file to use a platform-independent external parameter.

Acceptance Criteria fulfillment

• [✓] Identified the problem by debugging through the log file and confirmed it by replicating the issue in a dummy project with the same configuration.
• [✓] Updated the external parameter passed via the bundle function in the rollup configuration file, making it platform-independent.
• [✓] Referred to the issue link for details for the fix: Regex in external doesn't exclude local import rollup/rollup#3811
• [✓] Performed comprehensive testing on both Windows and Linux environments to ensure that it functions correctly.

Fixes #405

Video/Screenshots

Verification of the build process on Linux:
https://github.com/RocketChat/EmbeddedChat/assets/78961432/717b61d1-2f2b-43f9-91fb-b8faa275dbd8

Building process on Windows for verification:
https://github.com/RocketChat/EmbeddedChat/assets/78961432/1631d5b9-bd74-4022-be83-bd46340561ca

[abhinavkrin]

Thanks @Spiral-Memory Looks good to me. Great Find.