remove goto_programt::get_ and set_condition

[kroening]

This removes to methods that have been deprecated since October 2021,
together with its remaining uses.

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #6852 (a25657d) into develop (a188777) will decrease coverage by 0.00%.
The diff coverage is 67.18%.

@@             Coverage Diff             @@
##           develop    #6852      +/-   ##
===========================================
- Coverage    77.79%   77.79%   -0.01%     
===========================================
  Files         1567     1567              
  Lines       179707   179685      -22     
===========================================
- Hits        139797   139777      -20     
+ Misses       39910    39908       -2     

Impacted Files	Coverage Δ
src/analyses/flow_insensitive_analysis.cpp	74.64% <0.00%> (ø)
src/analyses/interval_analysis.cpp	0.00% <0.00%> (ø)
src/analyses/invariant_propagation.cpp	0.00% <0.00%> (ø)
src/analyses/invariant_set_domain.cpp	0.00% <0.00%> (ø)
src/analyses/static_analysis.cpp	46.69% <0.00%> (ø)
.../goto-instrument/accelerate/acceleration_utils.cpp	2.22% <0.00%> (ø)
...o-instrument/accelerate/polynomial_accelerator.cpp	0.00% <0.00%> (ø)
...goto-instrument/accelerate/sat_path_enumerator.cpp	57.89% <0.00%> (ø)
src/goto-instrument/branch.cpp	0.00% <0.00%> (ø)
src/goto-instrument/call_sequences.cpp	17.48% <0.00%> (ø)
... and 47 more

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