feat: list users scim v2 endpoint (#9187)

# Which Problems Are Solved
- Adds support for the list users SCIM v2 endpoint

# How the Problems Are Solved
- Adds support for the list users SCIM v2 endpoints under `GET
/scim/v2/{orgID}/Users` and `POST /scim/v2/{orgID}/Users/.search`

# Additional Changes
- adds a new function `SearchUserMetadataForUsers` to the query layer to
query a metadata keyset for given user ids
- adds a new function `NewUserMetadataExistsQuery` to the query layer to
query a given metadata key value pair exists
- adds a new function `CountUsers` to the query layer to count users
without reading any rows
- handle `ErrorAlreadyExists` as scim errors `uniqueness`
- adds `NumberLessOrEqual` and `NumberGreaterOrEqual` query comparison
methods
- adds `BytesQuery` with `BytesEquals` and `BytesNotEquals` query
comparison methods

# Additional Context
Part of #8140
Supported fields for scim filters:
* `meta.created`
* `meta.lastModified`
* `id`
* `username`
* `name.familyName`
* `name.givenName`
* `emails` and `emails.value`
* `active` only eq and ne
* `externalId` only eq and ne

internal/api/http/parser.go

@@ -1,6 +1,7 @@
 package http
 
 import (
+	"errors"
 	"net/http"
 
 	"github.com/gorilla/schema"
@@ -26,3 +27,24 @@ func (p *Parser) Parse(r *http.Request, data interface{}) error {
 
 	return p.decoder.Decode(data, r.Form)
 }
+
+func (p *Parser) UnwrapParserError(err error) error {
+	if err == nil {
+		return nil
+	}
+
+	// try to unwrap the error
+	var multiErr schema.MultiError
+	if errors.As(err, &multiErr) && len(multiErr) == 1 {
+		for _, v := range multiErr {
+			var schemaErr schema.ConversionError
+			if errors.As(v, &schemaErr) {
+				return schemaErr.Err
+			}
+
+			return v
+		}
+	}
+
+	return err
+}