fix(common): better defaults for curl initialization

[coryan]

By default, initialize libcurl with locking and signal handlers that work for most applications. In particular, leaving the default handler for SIGPIPE usually results in the application crashes when a socket is closed.

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This change is 

[google-cloud-cpp-bot]

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[dbolduc]

Should we have an Options CurlDefaultOptions(Options), where we can default these values to true (and test that the defaults are correct)?

Maybe we call it here:

google-cloud-cpp/google/cloud/internal/curl_rest_client.cc

Line 102 in 171f936

options_(std::move(options)) {

[codecov]

Codecov Report

Merging #9798 (678e839) into main (171f936) will increase coverage by 0.00%.
The diff coverage is 94.11%.

@@           Coverage Diff           @@
##             main    #9798   +/-   ##
=======================================
  Coverage   94.22%   94.22%           
=======================================
  Files        1495     1495           
  Lines      139801   139816   +15     
=======================================
+ Hits       131725   131744   +19     
+ Misses       8076     8072    -4     

Impacted Files	Coverage Δ
google/cloud/internal/curl_wrappers.cc	77.90% <83.33%> (-0.15%)	⬇️
google/cloud/internal/curl_wrappers_test.cc	100.00% <100.00%> (ø)
...e/cloud/pubsublite/internal/alarm_registry_impl.cc	97.05% <0.00%> (-2.95%)	⬇️
...le/cloud/internal/default_completion_queue_impl.cc	96.59% <0.00%> (-0.57%)	⬇️
...cloud/pubsub/internal/subscription_session_test.cc	97.98% <0.00%> (-0.17%)	⬇️
google/cloud/completion_queue_test.cc	97.32% <0.00%> (+0.19%)	⬆️
...bigtable/examples/bigtable_hello_instance_admin.cc	83.00% <0.00%> (+2.00%)	⬆️
...te/integration_tests/publisher_integration_test.cc	98.68% <0.00%> (+6.57%)	⬆️

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Google Cloud Build Logs
For commit: 678e8394a5cab519564d8b4f9f9356f1aaffa9a2

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[dbolduc]

Thanks