chore: cleanup setting config in instrumentations

[Flarna]

Short description of the changes

There is no need to create a copy of the config object as this is done in base class.
Remove defaulting to an empty config object at several places as this is done in the base class.
Remove the intersection type with InstrumentationConfig as all config types extend this type.
Avoid overriding the _config property in the grpc instrumentation.

[codecov]

Codecov Report

Merging #2522 (1e19790) into main (c0ab952) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2522      +/-   ##
==========================================
- Coverage   93.07%   93.07%   -0.01%     
==========================================
  Files         140      140              
  Lines        5172     5169       -3     
  Branches     1111     1101      -10     
==========================================
- Hits         4814     4811       -3     
  Misses        358      358              

Impacted Files	Coverage Δ
...emetry-instrumentation-grpc/src/instrumentation.ts	75.86% <0.00%> (-0.81%)	⬇️
...elemetry-instrumentation-grpc/src/grpc-js/index.ts	90.72% <0.00%> (-0.10%)	⬇️
...entelemetry-instrumentation-grpc/src/grpc/index.ts	92.98% <0.00%> (-0.07%)	⬇️
...ges/opentelemetry-instrumentation-http/src/http.ts	94.90% <0.00%> (ø)
...emetry-instrumentation-xml-http-request/src/xhr.ts	97.58% <0.00%> (ø)

[obecny]

I would add few other refactoring to have real typed getConfig

[obecny]

are you overriding this just to have correct type, if so I would rather do it differently by refactoring abstract class - something like this

export abstract class InstrumentationAbstract<T = types.InstrumentationConfig>
  implements types.Instrumentation {
  protected _config: T;
  constructor(
    public readonly instrumentationName: string,
    public readonly instrumentationVersion: string,
    config: T

It would require small refactoring of init method as well as InstrumentationModuleDefinition

export interface InstrumentationModuleDefinition<T = any> {

But then you would not have to worry about overriding the getConfig to have typed config from instrumentation class WDYT ?

[Flarna]

I tried that a while ago but failed. typescript complained at various places like

• the different default arguments in constructor of the concrete instrumentations
• no compatible base type for registerInstrumentation() arguments.

There is already a stalled PR from @dyladan regarding this: #2388

[dyladan]

My stalled PR was stalled because it was more difficult to get typescript to be happy than I anticipated when I started it. For now, I think doing it this way is probably fine.

I would like to make the types smarter eventually. I know it should be possible if someone has the time and inclination.