Ensure HTTP header values are redacted

[bart-vmware]

Description

By referencing v9 of Microsoft.Extensions.Http, we activate the breaking change that redacts all HTTP headers by default.

I have verified the behavior can be overruled from outside of Steeltoe using (globally):

builder.Services.ConfigureHttpClientDefaults(clientBuilder => clientBuilder.RedactLoggedHeaders(_ => false));

and locally:

builder.Services.AddHttpClient("CloudFoundrySecurity").RedactLoggedHeaders(_ => false);

Adding any of the lines above causes the test CloudFoundrySecurityMiddlewareTest.Redacts_HTTP_headers to fail.

Fixes #1447

Quality checklist

• Your code complies with our Coding Style.
• You've updated unit and/or integration tests for your change, where applicable.
• You've updated documentation for your change, where applicable.
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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[TimHess]

LGTM