fix(mocklib): fixed false positive file existence checks for mocks

[gouravkrosx]

• While recording mocks using mockLib, it was showing that mock already exists since the functionality was checking only the folder name and not the actual file in the path.
• Also updated readMe to show mock Library usage instructions.

Describe the changes you've made

• Updated the location to check for existing mocks, now it's mockpath+"/"+mockFileName.yaml.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, local variables)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Describe if there is any unusual behaviour of your code(Write NA if there isn't)

NA

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas and used java doc.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.

Screenshots (if any)

Original	Updated
original screenshot	updated screenshot