Tabulator: don't attempt to set text_align on Bokeh formatters that don't support it

[maximlt]

I got pretty much the same error as reported in #5915 and fixed in #5922, where the code fails while trying to set text_align on a Bokeh formatter that doesn't support this attribute. #5922 fixed that for the index but it applies to any other column too.

import pandas as pd
import panel as pn

from bokeh.models import HTMLTemplateFormatter

df = pd.DataFrame(dict(x=['a', 'b']))

pn.widgets.Tabulator(
    df,
    widths=300,
    text_align=dict(x='center'),
    formatters=dict(x=HTMLTemplateFormatter(template='<b><%= value %></b>'))
).servable()

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (7bc8c83) 84.42% compared to head (fb45da9) 38.31%.

Files	Patch %	Lines
panel/tests/widgets/test_tables.py	33.33%	4 Missing ⚠️
panel/widgets/tables.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6010       +/-   ##
===========================================
- Coverage   84.42%   38.31%   -46.12%     
===========================================
  Files         291      291               
  Lines       43576    43571        -5     
===========================================
- Hits        36789    16693    -20096     
- Misses       6787    26878    +20091     

Flag	Coverage Δ
ui-tests	38.31% <50.00%> (-2.43%)	⬇️
unitexamples-tests	?

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[philippjfr]

Merging, pyvista related example is failing but that was already fixed in a separate PR.