Panic due to Rect shape feathering

[PPakalns]

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