opentelemetry-instrumentation-urllib3: remove multiple calls to sanitize_method (#4718)

* opentelemetry-instrumentation-urllib3: remove multiple calls to sanitize_method

Instead call the method once and pass the results in where needed

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>

* changelog

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>

* fix lint

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>

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Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>
Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>