fix(subsonic): clearing playlist comment and public in Subsonic API (#4258)

* fix(subsonic): allow clearing playlist comment

* fix(playlists): simplify comment and public parameter handling

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(playlists): streamline fakePlaylists implementation in tests

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

utils/req/req_test.go

@@ -219,4 +219,59 @@ var _ = Describe("Request Helpers", func() {
 			})
 		})
 	})
+
+	Describe("ParamStringPtr", func() {
+		BeforeEach(func() {
+			r = req.Params(httptest.NewRequest("GET", "/ping?a=123", nil))
+		})
+
+		It("returns pointer to string if param exists", func() {
+			ptr := r.StringPtr("a")
+			Expect(ptr).ToNot(BeNil())
+			Expect(*ptr).To(Equal("123"))
+		})
+
+		It("returns nil if param does not exist", func() {
+			ptr := r.StringPtr("xx")
+			Expect(ptr).To(BeNil())
+		})
+
+		It("returns pointer to empty string if param exists but is empty", func() {
+			r = req.Params(httptest.NewRequest("GET", "/ping?a=", nil))
+			ptr := r.StringPtr("a")
+			Expect(ptr).ToNot(BeNil())
+			Expect(*ptr).To(Equal(""))
+		})
+	})
+
+	Describe("ParamBoolPtr", func() {
+		Context("value is true", func() {
+			BeforeEach(func() {
+				r = req.Params(httptest.NewRequest("GET", "/ping?b=true", nil))
+			})
+
+			It("returns pointer to true if param is 'true'", func() {
+				ptr := r.BoolPtr("b")
+				Expect(ptr).ToNot(BeNil())
+				Expect(*ptr).To(BeTrue())
+			})
+		})
+
+		Context("value is false", func() {
+			BeforeEach(func() {
+				r = req.Params(httptest.NewRequest("GET", "/ping?b=false", nil))
+			})
+
+			It("returns pointer to false if param is 'false'", func() {
+				ptr := r.BoolPtr("b")
+				Expect(ptr).ToNot(BeNil())
+				Expect(*ptr).To(BeFalse())
+			})
+		})
+
+		It("returns nil if param does not exist", func() {
+			ptr := r.BoolPtr("xx")
+			Expect(ptr).To(BeNil())
+		})
+	})
 })