[service] Start refactor of GetExporters

[TylerHelmuth]

Description

As part of #11204 I left host's implementation of GetExporters alone, thinking I didn't need to change a deprecated interface implementation.

But GetExporters depends on component.DataType, so we won't be able to remove component.DataType unless GetExporters is updated to use pipeline.Signal instead.

This PR deprecates the deprecated GetExporters interface with GetExportersWithSignal, which uses pipeline.Signal. Then we'll follow the process to rename GetExportersWithSignal back to GetExporters.

[TylerHelmuth]

@djaglowski @dmitryax @tigrannajaryan this is pretty annoying to do for an interface we already want to remove. It would be nice to keep progress moving on #7370

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.42%. Comparing base (66f41f9) to head (cc4faf4).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #11249   +/-   ##
=======================================
  Coverage   91.41%   91.42%           
=======================================
  Files         424      424           
  Lines       20198    20187   -11     
=======================================
- Hits        18465    18455   -10     
+ Misses       1349     1348    -1     
  Partials      384      384           

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