Support TextParameter pointing to UnionParameter

[farmio]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 95.23%. Comparing base (e5831bf) to head (1016d0a).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
xknxproject/util.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #481      +/-   ##
==========================================
- Coverage   95.37%   95.23%   -0.15%     
==========================================
  Files          22       22              
  Lines        1276     1280       +4     
==========================================
+ Hits         1217     1219       +2     
- Misses         59       61       +2     

Files with missing lines	Coverage Δ
xknxproject/exceptions/exceptions.py	100.00% <ø> (ø)
xknxproject/util.py	96.00% <66.66%> (-4.00%)	⬇️