Python: remove unnecessary class attributes from SKFunctionBase. (#4283)

### Motivation and Context

Fixes #4280. Currently, the str representation of SK functions look
verbose:

'uppercase': SKFunction(FUNCTION_PARAM_NAME_REGEX='^[0-9A-Za-z_]*$',
FUNCTION_NAME_REGEX='^[0-9A-Za-z_]*$',
SKILL_NAME_REGEX='^[0-9A-Za-z_]*$')

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### Description

This PR removes unnecessary class attributes from SKFunctionBase and
exposes some constants in utils/validation.

<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [X] The code builds clean without any errors or warnings
- [X] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [X] All unit tests pass, and I have added new tests where possible
- [X] I didn't break anyone 😄

---------

Co-authored-by: Evan Mattson <evan.mattson@microsoft.com>

python/semantic_kernel/orchestration/sk_function_base.py

@@ -23,10 +23,6 @@
 
 
 class SKFunctionBase(SKBaseModel):
-    FUNCTION_PARAM_NAME_REGEX: str = r"^[0-9A-Za-z_]*$"
-    FUNCTION_NAME_REGEX: str = r"^[0-9A-Za-z_]*$"
-    SKILL_NAME_REGEX: str = r"^[0-9A-Za-z_]*$"
-
     @property
     @abstractmethod
     def name(self) -> str:

python/semantic_kernel/utils/validation.py

@@ -3,6 +3,11 @@
 from re import match as re_match
 from typing import Optional
 
+# Validation regexes
+SKILL_NAME_REGEX = r"^[0-9A-Za-z_]*$"
+FUNCTION_NAME_REGEX = r"^[0-9A-Za-z_]*$"
+FUNCTION_PARAM_NAME_REGEX = r"^[0-9A-Za-z_]*$"
+
 
 def validate_skill_name(value: Optional[str]) -> None:
     """
@@ -18,7 +23,6 @@ def validate_skill_name(value: Optional[str]) -> None:
     if not value:
         raise ValueError("The skill name cannot be `None` or empty")
 
-    SKILL_NAME_REGEX = r"^[0-9A-Za-z_]*$"
     if not re_match(SKILL_NAME_REGEX, value):
         raise ValueError(
             f"Invalid skill name: {value}. Skill "
@@ -41,7 +45,6 @@ def validate_function_name(value: Optional[str]) -> None:
     if not value:
         raise ValueError("The function name cannot be `None` or empty")
 
-    FUNCTION_NAME_REGEX = r"^[0-9A-Za-z_]*$"
     if not re_match(FUNCTION_NAME_REGEX, value):
         raise ValueError(
             f"Invalid function name: {value}. Function "
@@ -64,7 +67,6 @@ def validate_function_param_name(value: Optional[str]) -> None:
     if not value:
         raise ValueError("The function parameter name cannot be `None` or empty")
 
-    FUNCTION_PARAM_NAME_REGEX = r"^[0-9A-Za-z_]*$"
     if not re_match(FUNCTION_PARAM_NAME_REGEX, value):
         raise ValueError(
             f"Invalid function parameter name: {value}. Function parameter "