test(general): Add some missing code coverage

[michaelbrewer]

Description of changes:

• test(DictWrapper): Add check for not isinstance
• test(tracing): Add mock to test aiohttp_trace_config
• test(appconfig): Add test for get_app_config() without a default provider

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

[michaelbrewer]

@cakepietoast some more clean up for the next release.

[heitorlessa]

One clarification and one tiny change - LGTM after that

[codecov-io]

Codecov Report

Merging #296 (c24add9) into develop (6e293b1) will increase coverage by 0.21%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #296      +/-   ##
===========================================
+ Coverage    99.65%   99.87%   +0.21%     
===========================================
  Files           90       90              
  Lines         3217     3217              
  Branches       153      153              
===========================================
+ Hits          3206     3213       +7     
+ Misses           7        2       -5     
+ Partials         4        2       -2     

Impacted Files	Coverage Δ
...lambda_powertools/utilities/data_classes/common.py	100.00% <0.00%> (+6.25%)	⬆️
...ambda_powertools/utilities/parameters/appconfig.py	100.00% <0.00%> (+6.89%)	⬆️
aws_lambda_powertools/tracing/extensions.py	100.00% <0.00%> (+75.00%)	⬆️

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[heitorlessa]

for the record faf75ca 😈