Add by-action captcha score config

Enable setting different captcha score thresholds for different captcha
actions via configuration

service/src/main/java/org/whispersystems/textsecuregcm/captcha/HCaptchaClient.java

@@ -9,6 +9,7 @@ import static org.whispersystems.textsecuregcm.metrics.MetricsUtil.name;
 
 import io.micrometer.core.instrument.Metrics;
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.net.URI;
 import java.net.URLEncoder;
 import java.net.http.HttpClient;
@@ -109,6 +110,8 @@ public class HCaptchaClient implements CaptchaClient {
           "reason", reason,
           "score", scoreString).increment();
     }
-    return new AssessmentResult(score >= config.getScoreFloor().floatValue(), scoreString);
+
+    final BigDecimal threshold = config.getScoreFloorByAction().getOrDefault(action, config.getScoreFloor());
+    return new AssessmentResult(score >= threshold.floatValue(), scoreString);
   }
 }

service/src/main/java/org/whispersystems/textsecuregcm/captcha/RecaptchaClient.java

@@ -18,6 +18,7 @@ import com.google.recaptchaenterprise.v1.RiskAnalysis;
 import io.micrometer.core.instrument.Metrics;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.nio.charset.StandardCharsets;
 import java.util.Objects;
 import javax.annotation.Nonnull;
@@ -99,8 +100,9 @@ public class RecaptchaClient implements CaptchaClient {
                 "reason", reason.name())
             .increment();
       }
+      final BigDecimal threshold = config.getScoreFloorByAction().getOrDefault(expectedAction, config.getScoreFloor());
       return new AssessmentResult(
-          score >= config.getScoreFloor().floatValue(),
+          score >= threshold.floatValue(),
           AssessmentResult.scoreString(score));
     } else {
       Metrics.counter(INVALID_REASON_COUNTER_NAME,

service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicCaptchaConfiguration.java

@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.annotations.VisibleForTesting;
 import java.math.BigDecimal;
 import java.util.Collections;
+import java.util.Map;
 import java.util.Set;
 import javax.validation.constraints.DecimalMax;
 import javax.validation.constraints.DecimalMin;
@@ -28,6 +29,11 @@ public class DynamicCaptchaConfiguration {
   @JsonProperty
   private boolean allowRecaptcha = true;
 
+
+  @JsonProperty
+  @NotNull
+  private Map<String, BigDecimal> scoreFloorByAction = Collections.emptyMap();
+
   @JsonProperty
   @NotNull
   private Set<String> signupCountryCodes = Collections.emptySet();
@@ -66,6 +72,10 @@ public class DynamicCaptchaConfiguration {
     return allowRecaptcha;
   }
 
+  public Map<String, BigDecimal> getScoreFloorByAction() {
+    return scoreFloorByAction;
+  }
+
   @VisibleForTesting
   public void setAllowHCaptcha(final boolean allowHCaptcha) {
     this.allowHCaptcha = allowHCaptcha;

service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java

@@ -262,6 +262,9 @@ class DynamicConfigurationTest {
             signupCountryCodes:
               - 1
             scoreFloor: 0.9
+            scoreFloorByAction:
+              challenge: 0.1
+              registration: 0.2
           """;
 
       final DynamicCaptchaConfiguration config =
@@ -270,6 +273,8 @@ class DynamicConfigurationTest {
 
       assertEquals(Set.of("1"), config.getSignupCountryCodes());
       assertEquals(0.9f, config.getScoreFloor().floatValue());
+      assertEquals(0.1f, config.getScoreFloorByAction().get("challenge").floatValue());
+      assertEquals(0.2f, config.getScoreFloorByAction().get("registration").floatValue());
     }
   }