[FIX] props validation: do not subscribe to props keys

In dev mode, owl inserts an additional props validation step. Before
this commit, the validation would iterate on all key/value pairs of each
props. If the props is reactive, this has the unfortunate side effect of
subscribing the component to each of the keys, even though it should not
be.

This commit avoids the issue by only validating the raw object.

tests/components/__snapshots__/props_validation.test.ts.snap

@@ -841,6 +841,33 @@ exports[`props validation props are validated whenever component is updated 2`]
 }"
 `;
 
+exports[`props validation props validation does not cause additional subscription 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, false);
+  
+  return function template(ctx, node, key = \\"\\") {
+    const props1 = {obj: ctx['obj']};
+    helpers.validateProps(\`Child\`, props1, this);
+    const b2 = comp1(props1, key + \`__1\`, node, this, null);
+    const b3 = text(ctx['obj'].otherValue);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`props validation props validation does not cause additional subscription 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['props'].obj.value);
+  }
+}"
+`;
+
 exports[`props validation props: list of strings 1`] = `
 "function anonymous(app, bdom, helpers
 ) {

tests/components/props_validation.test.ts

@@ -1,5 +1,5 @@
 import { makeTestFixture, nextAppError, nextTick, snapshotEverything } from "../helpers";
-import { Component, onError, xml, mount, OwlError } from "../../src";
+import { Component, onError, xml, mount, OwlError, useState } from "../../src";
 import { App, DEV_MSG } from "../../src/runtime/app";
 import { validateProps } from "../../src/runtime/template_helpers";
 import { Schema } from "../../src/runtime/validation";
@@ -682,6 +682,29 @@ describe("props validation", () => {
     expect(error!.message).toBe("Invalid props for component 'SubComp': 'p' is missing");
   });
 
+  test("props validation does not cause additional subscription", async () => {
+    let obj = {
+      value: 1,
+      otherValue: 2,
+    };
+    class Child extends Component {
+      static props = {
+        obj: { type: Object, shape: { value: Number, otherValue: Number } },
+      };
+      static template = xml`<t t-esc="props.obj.value"/>`;
+    }
+    class Parent extends Component {
+      static template = xml`<Child obj="obj"/><t t-esc="obj.otherValue"/>`;
+      static components = { Child };
+
+      obj = useState(obj);
+    }
+    const app = new App(Parent, { test: true });
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("12");
+    expect(app.root!.subscriptions).toEqual([{ keys: ["otherValue"], target: obj }]);
+  });
+
   test("props are validated whenever component is updated", async () => {
     let error: Error;
     class SubComp extends Component {