Cyclic Result Analysis Plotting

### 🔍 Before submitting the issue

- [X] I have searched among the existing issues
- [X] I am using a Python virtual environment

### 🐞 Description of the bug

I encounter some issues while trying to plot mode shape of cyclic analysis:

1) why do the colors merge on the colorbar in some cases? Is there a way to fix color ranges?

But in the other cases (cumulative indices) the colors are OK:

2) There is a commented parameter in cyclic_reader.py:
This affects on the plot for certain cumulative indices.
Could you please explain such behavior? Is there a way to automatically determine which formula we should use: result_combined = result - result_r * 1j or result_combined = result + result_r * 1j ?

### 📝 Steps to reproduce

```python
from ansys.mapdl import reader as pymapdl_reader
from ansys.mapdl.reader import examples

result = examples.download_sector_modal()
result.plot_nodal_displacement(15, show_displacement=True,displacement_factor=0.001,cpos="yz",show_scalar_bar=True,full_rotor=True,cmap=["blue","cyan","aquamarine","lime","greenyellow","yellow","orange","red"])
```

### 💻 Which operating system are you using?

Windows

### 📀 Which ANSYS version are you using?

I'm using built-in example download_sector_modal. Ansys v15.0 i guess

### 🐍 Which Python version are you using?

3.10

### 📦 Installed packages

```shell
ansys-mapdl-core==0.64.1
ansys-mapdl-reader==0.53.0
```

Start with the provided download_sector_modal and plot_nodal_displacement reproduction, then inspect cyclic_reader.py around the commented result_combined formulas. Compare the colorbar behavior and cyclic indices for both sign choices, and determine whether the issue can be resolved with a justified automatic rule; done means the plotting behavior and formula choice are verified and documented.

Written by the indexing model from the issue text.