Failed to parse json credential

### [READ] Step 1: Are you in the right place?

* For issues related to __the code in this repository__ file a GitHub issue.
* If the issue pertains to __Cloud Firestore__, report directly in the
[Python Firestore](https://github.com/googleapis/python-firestore) GitHub repo. Firestore
bugs reported in this repo will be closed with a reference to the Python Firestore
project.
* For general technical questions, post a question on [StackOverflow](http://stackoverflow.com/)
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[Firebase support channel](https://firebase.google.com/support/).

### [REQUIRED] Step 2: Describe your environment

* Operating System version: MacOS Sonoma 14.3.1
* Firebase SDK version: 6.5.0
* Firebase Product: auth
* Python version: 3.11.0
* Pip version: 24.0

### [REQUIRED] Step 3: Describe the problem

When calling `firebase_admin.credentials.Certificate`, occurred error `OSError`, which used not credential file path, but parsed json dictionary. I expect returning function `_is_file_path` `False` if used parameter as dictionary.

#### Steps to reproduce:

What happened? How can we make the problem occur?
This could be a description, log/console output, etc.

#### Relevant Code:

```
# firebase_admin/credentials.py
def _is_file_path(path):
try:
path_obj = pathlib.Path(path)
return True
except TypeError:
return False
```