fix: handle parameters for view filters

[jorwoods]

Closes #1632

Parameters need to be prefixed with "vf_Parameters." in order to be properly registered as setting a parameter value. This PR adds that prefix where it was missing, but leaves parameter names that already included the prefix unmodified.

[jorwoods]

To restate on the PR: copilot recommends changing "vf_Parameters" to "vf_parameters". But the Tableau Server query parameter is case sensitive, so it has to be "vf_Parameters". Below is a sample script I used to test this.

import os

from dotenv import load_dotenv
import tableauserverclient as TSC

load_dotenv()

server = TSC.Server(os.environ["TABLEAU_SERVER"], use_server_version=True)
auth = TSC.PersonalAccessTokenAuth(os.environ["TOKEN_NAME"], os.environ["TOKEN_SECRET"], site_id=os.environ["TABLEAU_SITE"])
with server.auth.sign_in(auth):
    view = server.views.filter(name="test", workbook_name="Superstore", project_name="Samples")[0]
    opts = TSC.CSVRequestOptions()
    opts.parameter("Check", "sent")
    server.views.populate_csv(view, opts)
    for line in view.csv:
        print(line.decode("utf-8").strip())