Fix type errors caught by pyright but not mypy

[tpoliaw]

• Use type as type of Inputs/Outputs fields
• Use correct types instead of string literals in tests
• Use Iterator instead of Iterable as the return type when wrapping
• Check optional keys are present before access
• Ignore type checking of dynamic softioc dbl method
• Strengthen type handling of strings vs bytes in interpreters/adapters

Where type checking has been ignored, comments have been added to explain why the code is still valid.

[codecov[bot]]

Codecov Report

Merging #156 (a7dc12d) into master (6066902) will decrease coverage by 0.08%. The diff coverage is 93.54%.

@@            Coverage Diff             @@
##           master     #156      +/-   ##
==========================================
- Coverage   94.50%   94.42%   -0.08%     
==========================================
  Files          44       44              
  Lines        1292     1310      +18     
==========================================
+ Hits         1221     1237      +16     
- Misses         71       73       +2     

Impacted Files	Coverage Δ
src/tickit/adapters/epicsadapter/ioc_manager.py	59.37% <0.00%> (ø)
src/tickit/core/state_interfaces/kafka.py	83.33% <0.00%> (-2.88%)	:arrow_down:
src/tickit/utils/configuration/tagged_union.py	87.23% <ø> (ø)
...kit/adapters/interpreters/command/regex_command.py	96.15% <94.44%> (-3.85%)	:arrow_down:
src/tickit/adapters/epicsadapter/adapter.py	100.00% <100.00%> (ø)
...apters/interpreters/command/command_interpreter.py	96.77% <100.00%> (+0.10%)	:arrow_up:
src/tickit/adapters/interpreters/utils.py	100.00% <100.00%> (ø)
...pters/interpreters/wrappers/joining_interpreter.py	100.00% <100.00%> (ø)
...ers/interpreters/wrappers/splitting_interpreter.py	100.00% <100.00%> (ø)
...rc/tickit/core/state_interfaces/state_interface.py	88.23% <100.00%> (ø)
... and 3 more

[tpoliaw]

There are still a few (6) errors remaining but mostly around the interpreters which I'd like to overhaul slightly anyway

[tpoliaw]

Up to you but I think I'd go for a separate PR so it can be rolled back more easily if there's a pyright problem we can't work around. Everything in this PR should still be valid if we stick with mypy.

[abbiemery]

Agree. In which case either resolve the issue in the push device or make a new issue for it, and merge this :)

[tpoliaw]

make a new issue for it

170