Default fonts are included on `eframe` builds without the `default_fonts` feature

**Describe the bug**
Default fonts always seem to be included when building a binary with eframe, even if the feature flag is disabled. The built binary contains the byte sequence of the font files included with `include_bytes!`.

**To Reproduce**
Build a project where `eframe` is included with `default-features = false`.

**Expected behavior**
Default fonts should not be included if the `default_fonts` flag is not set.

**Desktop (please complete the following information):**
- OS: macOS 13.5

**Additional context**
I didn't test if the flag works on `egui` itself, this was only tested with `eframe`.

Start by reproducing the issue in an eframe project built with default-features = false, then inspect the eframe feature configuration and the font references using include_bytes!. Confirm the default font byte sequence is absent from the resulting binary; the issue is done when default_fonts remains disabled and those fonts are no longer included.

Written by the indexing model from the issue text.