Fix drawing headerless colored tables with title

[kuba2k2]

The pull request #299 (issue #290) fixed drawing ColorTable with a title set. However, it didn't fix drawing such a table with header set to False.

This PR fixes that; there was some incorrect line slicing that led to ANSI codes being cut off partially.

Here's how it looks without this PR:

+-----------------------+
|        Efforts        |
+[36m+---+---+---+---+---+---+ 1 | 2 | 3 | 4 | 5 | 6 |
+---+---+---+---+---+---+

and with this PR - the correct result:

+-----------------------+
|        Efforts        |
+---+---+---+---+---+---+
| 1 | 2 | 3 | 4 | 5 | 6 |
+---+---+---+---+---+---+

Produced by this code:

from prettytable import colortable

table = colortable.ColorTable(
    ("A", "B", "C", "D", "E", "f"),
    align="l",
    theme=colortable.Themes.OCEAN,
)
table.title = "Efforts"
table.header = False
table.add_row([1, 2, 3, 4, 5, 6])
print(table)

I have also added parametrized tests to the test_colortable.py, so that it will test all possible cases of header/title combinations.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.57%. Comparing base (f044b0e) to head (fa57608).
Report is 32 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #332      +/-   ##
==========================================
+ Coverage   94.51%   94.57%   +0.06%     
==========================================
  Files           5        5              
  Lines        2462     2637     +175     
==========================================
+ Hits         2327     2494     +167     
- Misses        135      143       +8     

Flag	Coverage Δ
macos-latest	94.53% <100.00%> (+0.02%)	⬆️
ubuntu-latest	94.53% <100.00%> (+0.02%)	⬆️
windows-latest	94.49% <100.00%> (?)

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