[AIRFLOW-6519] Make TI logs constants in Webserver configurable

[kaxil]

Some of the TaskInstance logs constants in the webserver (in ti_log.html) can be made configurable.

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Issue link: AIRFLOW-6519

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[schnie]

Awesome, this will be a good use for the new helm upgrader hook. We can set a higher value here and push it out to all deployments.

[codecov-io]

Codecov Report

Merging #7113 into master will increase coverage by 0.17%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #7113      +/-   ##
==========================================
+ Coverage   85.04%   85.22%   +0.17%     
==========================================
  Files         682      682              
  Lines       39000    39000              
==========================================
+ Hits        33169    33236      +67     
+ Misses       5831     5764      -67

Impacted Files	Coverage Δ
airflow/www/app.py	94.02% <ø> (ø)	⬆️
airflow/jobs/scheduler_job.py	89.29% <0%> (+1.17%)	⬆️
airflow/utils/sqlalchemy.py	96.66% <0%> (+6.66%)	⬆️
airflow/utils/dag_processing.py	87.95% <0%> (+6.88%)	⬆️
airflow/utils/helpers.py	81.69% <0%> (+7.18%)	⬆️
airflow/executors/sequential_executor.py	88% <0%> (+32%)	⬆️

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