Add EGL macro check before using eglGetProcAddress()

[adamscott]

Add a check for the macro definition EGL_ENABLED before using eglGetProcAddress().

Relates to #87981, where I thought that eglGetProcAddress() would have been used by the web platform. After more checks, it shouldn't be used.
Complements #93489 for the same reason.

[dsnopek]

The change in this PR is unnecessary in the context of the Web.

The code in question is already wrapped in #ifdef CAN_DEBUG, and CAN_DEBUG already won't be defined on the web. See:

godot/drivers/gles3/rasterizer_gles3.cpp

Lines 73 to 77 in b75f048

	#if !defined(IOS_ENABLED) && !defined(WEB_ENABLED)
	// We include EGL below to get debug callback on GLES2 platforms,
	// but EGL is not available on iOS.
	#define CAN_DEBUG
	#endif

[adamscott]

Not useful as stated by @bruvzg on the developers chat and by @dsnopek's comment.