We don't check if string provided as scheduled_execution_date is a genuine datetime

### 🔍 Before submitting the issue

- [x] I have searched among the existing issues
- [x] I am using a Python virtual environment

### 🐞 Description of the bug

It’s possible to provide a scheduled_execution_date in form of , and it works ok when provided value is an actual date but it falis when it only "looks like a date" i.e.: ”2024-1-0”.

In such cases we send it to the serverapi 'as is' and it result in a ‘Bad request’ response:

```
Traceback (most recent call last):
File "C:\Automation\STK\STKTests\jobqueue\jobqueue-smoke-test.py", line 252, in
import_job = api_client.create_job_and_wait(job_request=import_request)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\jobqueue\_connection.py", line 354, in create_job_and_wait
job = self.create_job(job_request=job_request)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\jobqueue\_connection.py", line 398, in create_job
job_response = self.job_queue_api.create_job(body=job_request._get_job_for_submission())
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\serverapi_openapi\api\job_queue_api.py", line 64, in create_job
data = self._create_job_with_http_info(body, _return_http_data_only=True)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\serverapi_openapi\api\job_queue_api.py", line 107, in _create_job_with_http_info
return self.api_client.call_api(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 475, in call_api
return self.__call_api(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 196, in __call_api
response_data = self.request(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 563, in request
return handle_response(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_util.py", line 380, in handle_response
raise ApiException.from_response(response)
ansys.openapi.common._exceptions.ApiException: ApiException(400, 'Bad Request')
HTTP response headers: {'Cache-Control': 'private', 'Content-Type': 'application/json; charset=utf-8', 'Server': 'Microsoft-IIS/10.0', 'Persistent-Auth': 'true', 'X-Frame-Options': 'SAMEORIGIN', 'X-Content-Type-Options': 'nosniff', 'Strict-Transport-Security': 'max-age=31536000', 'Date': 'Thu, 14 Nov 2024 12:23:03 GMT', 'Content-Length': '131'}
HTTP response body: {"scheduledExecutionDate":["Could not convert string to DateTime: 2024-1-0. Path 'scheduledExecutionDate', line 1, position 401."]}`
```

additionally:

“2024-1“ value results in “status: "JobStatus.Succeeded"“ (it shouldn't)
but
but ‘2024’ results in:

```
Traceback (most recent call last):
File "C:\Automation\STK\STKTests\jobqueue\jobqueue-smoke-test.py", line 252, in
import_job = api_client.create_job_and_wait(job_request=import_request)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\jobqueue\_connection.py", line 354, in create_job_and_wait
job = self.create_job(job_request=job_request)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\jobqueue\_connection.py", line 398, in create_job
job_response = self.job_queue_api.create_job(body=job_request._get_job_for_submission())
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\serverapi_openapi\api\job_queue_api.py", line 64, in create_job
data = self._create_job_with_http_info(body, _return_http_data_only=True)
File "C:\Program Files\Python313\Lib\site-packages\ansys\grantami\serverapi_openapi\api\job_queue_api.py", line 107, in _create_job_with_http_info
return self.api_client.call_api(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 475, in call_api
return self.__call_api(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 196, in __call_api
response_data = self.request(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_api_client.py", line 563, in request
return handle_response(
File "C:\Program Files\Python313\Lib\site-packages\ansys\openapi\common\_util.py", line 380, in handle_response
raise ApiException.from_response(response)
ansys.openapi.common._exceptions.ApiException: ApiException(400, 'Bad Request')
HTTP response headers: {'Cache-Control': 'private', 'Content-Type': 'application/json; charset=utf-8', 'Server': 'Microsoft-IIS/10.0', 'Persistent-Auth': 'true', 'X-Frame-Options': 'SAMEORIGIN', 'X-Content-Type-Options': 'nosniff', 'Strict-Transport-Security': 'max-age=31536000', 'Date': 'Thu, 14 Nov 2024 12:30:17 GMT', 'Content-Length': '127'}
HTTP response body: {"scheduledExecutionDate":["Could not convert string to DateTime: 2024. Path 'scheduledExecutionDate', line 1, position 397."]}`
```

### 📝 Steps to reproduce

prepare ExcelImportJobRequest where one of files parameter is a path to a folder, and create a job with it

```python
import_request = jobqueue.ExcelImportJobRequest(
name = "name",
description = "description",
template_file = ".\\myTemplate.xls",
data_files = [".\\myDataFile.xml"],
scheduled_execution_date = "2024-1-0",
)

import_job = api_client.create_job_and_wait(job_request=import_request)
```

### 💻 Which operating system are you using?

Windows

### 📀 Which ANSYS version are you using?

ansys-grantami-jobqueue 1.1.0rc0
ansys-grantami-serverapi-openapi 4.0.0
ansys-openapi-common 2.2.0
GRANTA_MIScriptingToolkit 4.1.75

Granta MI b. 25.1.1888

### 🐍 Which Python version are you using?

3.13

### 📦 Installed packages

```shell
ansys-grantami-jobqueue==1.1.0rc0
ansys-grantami-recordlists==1.3.0rc0
ansys-grantami-serverapi-openapi==4.0.0
ansys-openapi-common==2.2.0
certifi==2024.8.30
cffi==1.17.1
charset-normalizer==3.4.0
cryptography==43.0.3
filetype==1.2.0
GRANTA_MIScriptingToolkit @ file:///C:/Automation/STK/scripting-toolkit-4-1-75/pip/granta_miscriptingtoolkit-4.1.75-cp38-abi3-win_amd64.whl#sha256=7be8c6e46f63c29c0fde2a30911b2c3a607c5fb6443258b56e77339ca4db58b0
idna==3.10
jaraco.classes==3.4.0
jaraco.context==6.0.1
jaraco.functools==4.1.0
keyring==25.5.0
more-itertools==10.5.0
packaging==24.2
pycparser==2.22
pyparsing==3.2.0
pypiwin32==223
pyspnego==0.11.2
python-dateutil==2.9.0.post0
pywin32==308
pywin32-ctypes==0.2.3
requests==2.32.3
requests-negotiate-sspi==0.5.2
requests_ntlm==1.3.0
six==1.16.0
sspilib==0.2.0
urllib3==2.2.3
```

Start at ExcelImportJobRequest and the create_job_and_wait path described in the report, then inspect how scheduled_execution_date is serialized before the server request. Reproduce the cases 2024-1-0, 2024-1, and 2024, and add coverage showing invalid date-like strings are rejected before submission while genuine datetimes remain accepted.

Written by the indexing model from the issue text.