chore(exporter/zipkin): improves logging on invalid collector.

[jcchavezs]

ATM logs for invalid collector URL are kind of helpless. This PR improves the logs to be actionable.

Ping @bogdandrutu

[MrAlias]

It looks like tests need to be updated to match these changes.

[codecov]

Codecov Report

Merging #2191 (5ec479c) into main (c0c5ef6) will decrease coverage by 0.0%.
The diff coverage is 50.0%.

@@           Coverage Diff           @@
##            main   #2191     +/-   ##
=======================================
- Coverage   72.9%   72.9%   -0.1%     
=======================================
  Files        176     176             
  Lines      12161   12161             
=======================================
- Hits        8870    8867      -3     
- Misses      3053    3055      +2     
- Partials     238     239      +1     

Impacted Files	Coverage Δ
exporters/zipkin/zipkin.go	69.7% <50.0%> (ø)
...s/otlp/otlptrace/internal/connection/connection.go	14.8% <0.0%> (-1.6%)	⬇️

[jcchavezs]

Done @MrAlias