Fix #639 is_enterprise_install does not exist in context object

[seratch]

This pull request resolves #639

Category (place an x in each of the [ ])

• slack_bolt.App and/or its core components
• slack_bolt.async_app.AsyncApp and/or its core components
• Adapters in slack_bolt.adapter
• Document pages under /docs
• Others

Requirements (place an x in each [ ])

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've run ./scripts/install_all_and_run_tests.sh after making the changes.

[codecov]

Codecov Report

Merging #640 (616ec6a) into main (8df95d5) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #640   +/-   ##
=======================================
  Coverage   92.03%   92.04%           
=======================================
  Files         170      170           
  Lines        5791     5792    +1     
=======================================
+ Hits         5330     5331    +1     
  Misses        461      461           

Impacted Files	Coverage Δ
slack_bolt/__init__.py	100.00% <ø> (ø)
slack_bolt/adapter/django/handler.py	88.50% <ø> (ø)
slack_bolt/async_app.py	100.00% <ø> (ø)
slack_bolt/context/ack/internals.py	90.62% <ø> (ø)
slack_bolt/listener/builtins.py	100.00% <ø> (ø)
slack_bolt/middleware/ssl_check/ssl_check.py	93.10% <ø> (ø)
slack_bolt/oauth/internals.py	98.21% <ø> (ø)
slack_bolt/adapter/aws_lambda/__init__.py	100.00% <100.00%> (ø)
slack_bolt/adapter/bottle/__init__.py	100.00% <100.00%> (ø)
slack_bolt/adapter/cherrypy/__init__.py	100.00% <100.00%> (ø)
... and 29 more

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