Packet diagrams misalign or drop bitfields
## Summary
When configured to show packet diagrams in one of the panes, Wireshark has trouble showing some of the bitfields found in certain protocols.
## Steps to reproduce
1. Change layout configuration to show the packet diagram in the third pane.
2. Open `mpls_basic.cap` from the Wiki [SampleCaptures](https://wiki.wireshark.org/SampleCaptures)
3. Select frame 8 and compare the EIGRP layout shown in the packet details pane vs. packet diagram.
4. Select frame 9 and compare the MPLS layout shown in the packet details pane vs. packet diagram.
## What is the current bug behavior?
In frame 8 of `mpls_basic.cap` in the packet diagram pane the EIGRP flags field is aligned on the MSB of the 32 bit word, while it is shown to be in the LSB in the packet details pane.
In frame 9 of `mpls_basic.cap` in the packet diagram pane the MPLS TTL is not shown at all, while it occupies the space remaining in the 32 bit word after mpls.bottom.
## What is the expected correct behavior?
The eigrp.flags and mpls.ttl fields are presented in the correct location in the packet diagram. The same would be true for any other bitfields.
## Sample capture file
Use `mpls_basic.cap` from the Wiki [SampleCaptures](https://wiki.wireshark.org/SampleCaptures)
## Relevant logs and/or screenshots
Example of EIGRP
{width=798 height=836}
Example of MPLS
{width=798 height=619}
## Build information
```
Version 4.4.6 (v4.4.6rc0-79-g888677a4e1d9).
Compiled (64-bit) using GCC 14.2.0, with GLib 2.84.1, with Qt 6.8.2, with
libpcap, with POSIX capabilities (Linux), with libnl 3, with zlib 1.3.1, without
zlib-ng, with PCRE2, with Lua 5.4.7, with GnuTLS 3.8.9 and PKCS #11 support,
with Gcrypt 1.11.0, with Kerberos (MIT), with MaxMind, with nghttp2 1.64.0, with
nghttp3 1.8.0, with brotli, with LZ4, with Zstandard, with Snappy, with libxml2
2.9.14, with libsmi 0.5.0, without Minizip, with QtMultimedia, with QtDBus,
without automatic updates, with binary plugins.
Running on Linux 6.12.21-amd64, with Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz
(with SSE4.2), with 15689 MB of physical memory, with GLib 2.84.1, with Qt
6.8.2, with libpcap 1.10.5 (with TPACKET_V3), with zlib 1.3.1, with PCRE2 10.45
2025-02-05, with c-ares 1.34.5, with GnuTLS 3.8.9, with Gcrypt 1.11.0, with
nghttp2 1.64.0, with nghttp3 1.8.0, with brotli 1.1.0, with LZ4 1.10.0, with
Zstandard 1.5.7, with libsmi 0.5.0, with light display mode, without HiDPI, with
Xorg, with QPA plugin "xcb", with LC_TYPE=en_US.UTF-8, binary plugins supported.
```
issue