ng test does not run tests from new test files when watching

### Command

test

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

While `ng test` is running and watching for changes, if you add a new test file, that file is detected and causes the tests to run again, but the tests in that new file are not included in the test run. To include the tests from the new file, you need to restart the `ng test` process.

### Minimal Reproduction

1. In a terminal, run:
```
ng new watch --skip-git --style css --ssr=false
ng test
```

2. Three tests are run.
3. In a second terminal, run:
```
ng g component widget
```

4. A new component is created with a test file that contains one test.
5. The new test file is detected and the tests recompile.
6. **Only three tests are run.**
7. Add another test to the new component's test file.
8. The change is detected and the tests recompile.
9. **Only three tests are run.**
10. Kill the `ng test` process.
11. Run `ng test` again.
12. **Five tests are run.**

### Exception or Error

_No response_

### Your Environment

```text
_ _ ____ _ ___
/ \ _ __ __ _ _ _| | __ _ _ __ / ___| | |_ _|
/ △ \ | '_ \ / _` | | | | |/ _` | '__| | | | | | |
/ ___ \| | | | (_| | |_| | | (_| | | | |___| |___ | |
/_/ \_\_| |_|\__, |\__,_|_|\__,_|_| \____|_____|___|
|___/

Angular CLI: 17.0.3
Node: 20.9.0
Package Manager: npm 10.1.0
OS: win32 x64

Angular:
...

Package Version
------------------------------------------------------
@angular-devkit/architect 0.1700.3 (cli-only)
@angular-devkit/core 17.0.3 (cli-only)
@angular-devkit/schematics 17.0.3 (cli-only)
@schematics/angular 17.0.3 (cli-only)
```

### Anything else relevant?

Here's a screen recording to help explain what I'm seeing.

Reproduziere das Verhalten mit den aufgelisteten Befehlen `ng new`, `ng test` und `ng g component widget`, und verfolge anschließend den Watch-Ablauf von `ng test`, der die neue Testdatei erkennt und neu kompiliert. Vergleiche die initialen und die neu gestarteten Testläufe; als erledigt gilt die Aufgabe, wenn Tests in neu hinzugefügten Dateien während des Watchens ausgeführt werden, ohne den Prozess neu zu starten.

Vom Indexierungsmodell aus dem Issue-Text verfasst.