web-api(fix): revert use of export type * to maintain backwards compatibility with TS 4.7

[filmaj]

Also add an "integration test" to ensure integrating web-api in a project with TS 4.7.2 works.

This fixes #1840.

FYI @742617000027

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.85%. Comparing base (e678aff) to head (972fd7b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1841   +/-   ##
=======================================
  Coverage   81.85%   81.85%           
=======================================
  Files          35       35           
  Lines        7781     7781           
  Branches      318      318           
=======================================
  Hits         6369     6369           
  Misses       1400     1400           
  Partials       12       12           

Flag	Coverage Δ
cli-hooks	94.94% <ø> (ø)
cli-test	54.16% <ø> (ø)
oauth	76.53% <ø> (ø)
socket-mode	59.59% <ø> (ø)
web-api	96.57% <ø> (ø)
webhook	95.27% <ø> (ø)

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