[BUG] Process tree rendering

[Denizantip]

Read the README.md and search for similar issues before posting a bug report!

Any bug that can be solved by just reading the prerequisites section of the README will likely be ignored.

Describe the bug

In BTOP, the process tree rendering works incorrectly. Redundant pipe characters.

In bpytop, it works correctly

To Reproduce

Turn tree view in btop.

Expected behavior

Expectation is exact like in bpython:
After last child no continuation of pipe characters

Screenshots

[If applicable, add screenshots to help explain your problem.]

Info (please complete the following information):

• btop++ version: 1.3.0
• Binary: self compiled
• Architecture: x86_64
• Platform: Linux
• (Linux) Kernel: 6.8.0-45-generic
• (OSX/FreeBSD) Os release version: Ubuntu 24.04
• Terminal used: GNOME Terminal 3.52.0 using VTE 0.76.0 +BIDI +GNUTLS +ICU +SYSTEMD
• Font used: Terminuss Nerd