Panic due to Rect shape feathering #5664
Description
Describe the bug
When scaling UI if rendered Rect gets too small it may cause panic due to Rect being too small in some dimension and feathering was applied incorrectly (Not taking into account assert in inner function)
To Reproduce
Render small Rect under feathering threshold with texture_id set to non default value.
Expected behavior
If Rect can not be feathered, do not try to feather it.
Additional context
Egui version: 0.30
Stacktrace:
thread 'main' panicked at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/mesh.rs:151:9:
assertion failed: self.texture_id == TextureId::default()
stack backtrace:
0: rust_begin_unwind
at /rustc/a730edcd67c7cb29d4458e170d4eb290387c27c3/library/std/src/panicking.rs:695:5
1: core::panicking::panic_fmt
at /rustc/a730edcd67c7cb29d4458e170d4eb290387c27c3/library/core/src/panicking.rs:75:14
2: core::panicking::panic
at /rustc/a730edcd67c7cb29d4458e170d4eb290387c27c3/library/core/src/panicking.rs:145:5
3: colored_vertex
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/mesh.rs:151:9
4: stroke_path
5: stroke_open
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:482:9
6: tessellate_line<epaint::stroke::Stroke>
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:1587:9
7: tessellate_rect
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:1705:17
8: tessellate_shape
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:1394:17
9: tessellate_clipped_shape
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:1346:13
10: tessellate_shapes
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/epaint/src/tessellator.rs:2013:17
11: {closure#0}
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/egui/src/context.rs:2554:17
12: write<alloc::vec::Vec<epaint::ClippedPrimitive, alloc::alloc::Global>, egui::context::{impl#18}::tessellate::{closure_env#0}>
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/egui/src/context.rs:775:9
13: egui::context::Context::tessellate
at /home/pakalns/.cargo/git/checkouts/egui-f290029b5e1afa28/942690e/crates/egui/src/context.rs:2532:9
14: process_output_system