refactor(browser-detector): fix eslint warning

[chancancode]

Which problem is this PR solving?

Fixes the following eslint warning

/home/runner/work/opentelemetry-js/opentelemetry-js/experimental/packages/opentelemetry-browser-detector/src/BrowserDetector.ts
  66:66  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any

Ref #5365

Short description of the changes

Use an appropriate type for the task in place of any

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• eslint

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 94.63%. Comparing base (199fd8d) to head (ad57536).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
...ntelemetry-browser-detector/src/BrowserDetector.ts	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5384   +/-   ##
=======================================
  Coverage   94.63%   94.63%           
=======================================
  Files         318      318           
  Lines        8036     8036           
  Branches     1685     1685           
=======================================
  Hits         7605     7605           
  Misses        431      431           

Files with missing lines	Coverage Δ
...ntelemetry-browser-detector/src/BrowserDetector.ts	13.33% <0.00%> (ø)