[Bug]: apply_settings() hits the database on every call #5445

Description

apply_settings() hits the database on every call

File: esp/esp/program/modules/handlers/creditcardmodule_stripe.py

Problem

apply_settings() performs a database query and JSON parse on every invocation. Since get_setting() delegates directly to apply_settings(), any code path that calls get_setting() multiple times (e.g. payonline, charge_payment) triggers redundant DB hits within a single request.

def get_setting(self, name, default=None):
    return self.apply_settings().get(name, default)  # re-runs every time

Suggested Fix

Memoize the result on the instance so the DB is only queried once:

def apply_settings(self):
    if hasattr(self, '_settings_cache'):
        return self._settings_cache
    DEFAULTS = {
        'offer_donation': True,
        'donation_text': 'Donation to Learning Unlimited',
        'donation_options': [10, 20, 50],
        'invoice_prefix': settings.INSTITUTION_NAME.lower(),
    }
    DEFAULTS.update(settings.STRIPE_CONFIG)
    tag_data = json.loads(Tag.getProgramTag('stripe_settings', self.program))
    self._settings_cache = {**DEFAULTS, **tag_data}
    return self._settings_cache

Unnecessary repeated DB queries and JSON parsing on every page load of the payment flow.

Steps to Reproduce

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Expected Behavior

Settings for a given module instance should be loaded once per request and reused.

Actual Behavior

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Screenshots

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Operating System

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Browser

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Additional Context

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