Fix #20478: Remove output.globalObject from webpack config

[jagadish-555]

Description

This PR fixes a compatibility issue with Next.js 16 where importing pdfjs-dist causes an Object.defineProperty error.

The issue arises because the combination of outputModule: true and output.globalObject: "globalThis" in the Webpack configuration generates code that is incompatible with the Webpack runtime used by Next.js (specifically when using eval-based source maps).

Changes

• Removed output.globalObject = "globalThis" from gulpfile.mjs

This setting is unnecessary for ES Module builds (library.type: "module") and removing it resolves the conflict, allowing pdfjs-dist to be imported correctly in Next.js environments.

Fixes #20478

[calixteman]

This setting is unnecessary for ES Module builds ...

Could you give some pointers about that ?

[jagadish-555]

This setting is unnecessary for ES Module builds ...

Could you give some pointers about that ?

ESM builds do not use the global object at all. They rely purely on import/export.
output.globalObject only applies to non-ESM formats (UMD/IIFE).
Leaving it in forces Webpack to inject unnecessary global-handling code, which conflicts with Next.js 16's runtime.
Removing it produces a correct ESM output.