Add early return when angles are equal in DrawCircleSector and DrawCircleSectorLine functions.

[theundergroundsorcerer]

This change adds early return to circle sector drawing functions DrawCircleSector and DrawCircleSectorLines
when startAngle equals endAngle, matching the existing behavior in DrawRing and
DrawRingLines functions.

Benefits:

• Prevents unnecessary calculations when there's nothing to draw
• Avoids potential division by zero when angles are equal and segments=0
• Makes behavior consistent with the ring drawing functions

I've tested these changes on a Mac (no access to a Windows machine at the moment) and they don't break the build.
(In particular, shapes_draw_circle_sector example works the same way as before).

A Suggestion - perhaps comparing the difference to EPSILON defined in raylib.h is a better approach for all these functions.

[raysan5]

@theundergroundsorcerer Merged this quick fix because there are already other functions using same approach but:

• Comparing two float with == is not reliable, EPSILON should be used.
• I try to avoid early returns in raylib as much as possible, unfortunately in the last few years many have been added...

[theundergroundsorcerer]

Is it okay if I update all these functions to use EPSILON instead of 0? Or leave it as it is for now?

Just for the curiosity:
These functions do not return anything, using early return is equivalent to not drawing anything if there is nothing to draw. Is it still considered as an"early return"?