Add the browser version URL in OAuth completion page

[seratch]

This pull request brings slackapi/python-slack-sdk#963 improvements to Bolt for Java. This is just an improvement on the default page rendering. If an app serves its own web pages, this change does not affect the app.

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

• bolt (Bolt for Java)
• bolt-{sub modules} (Bolt for Java - optional modules)
• slack-api-client (Slack API Clients)
• slack-api-model (Slack API Data Models)
• slack-api-*-kotlin-extension (Kotlin Extensions for Slack API Clients)
• slack-app-backend (The primitive layer of Bolt for Java)

Requirements

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

[codecov]

Codecov Report

Merging #702 (b53911f) into main (1208c2a) will increase coverage by 0.00%.
The diff coverage is 75.00%.

@@            Coverage Diff            @@
##               main     #702   +/-   ##
=========================================
  Coverage     77.32%   77.33%           
  Complexity     3225     3225           
=========================================
  Files           361      361           
  Lines          9543     9546    +3     
  Branches        913      913           
=========================================
+ Hits           7379     7382    +3     
  Misses         1622     1622           
  Partials        542      542           

Impacted Files	Coverage Δ	Complexity Δ
...ault_impl/OAuthDefaultRedirectUriPageRenderer.java	42.10% <75.00%> (+10.85%)	4.00 <0.00> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1208c2a...2d78479. Read the comment docs.