False positive on token_fail_reason

Describe the bug

Up until this latest release, our bandit workflows have delivered passing results without issue. With our latest commit, 1.7.3 was installed and our unit testing failed with the following:

Issue: [B105:hardcoded_password_string] Possible hardcoded password: 'Unexpected API response received'
   Severity: Low   Confidence: Medium
   CWE: CWE-[25](https://github.com/CrowdStrike/falconpy/runs/5401017629?check_suite_focus=true#step:5:25)9 (https://cwe.mitre.org/data/definitions/259.html)
   Location: src/falconpy/oauth2.py:157:41
   More Info: https://bandit.readthedocs.io/en/1.7.3/plugins/b105_hardcoded_password_string.html
156	                returned = generate_error_result("Unexpected API response received", 403)
157	                self.token_fail_reason = "Unexpected API response received"
158	                self.token_status = 403

Impacted code block

if isinstance(returned, dict):
    self.token_status = returned["status_code"]
    if self.token_status == 201:
        self.token_expiration = returned["body"]["expires_in"]
        self.token_time = time.time()
        self.token_value = returned["body"]["access_token"]
        self.token_fail_reason = None
        # unrelated code continues...
else:
    returned = generate_error_result("Unexpected API response received", 403)
    self.token_fail_reason = "Unexpected API response received"
    self.token_status = 403

Reproduction steps

Started occurring with the 1.7.3 install. (I've confirmed it's not an issue in 1.7.0 - 1.7.2)

Expected behavior

I don't believe there is a problem with the code above.

Bandit version

1.7.3 (Default)

Python version

3.10 (Default)

Additional context

Appears to be similar to issue #842.

Start by inspecting the B105 hardcoded_password_string plugin and comparing its behavior between Bandit 1.7.2 and 1.7.3. Reproduce the report using the shown src/falconpy/oauth2.py token_fail_reason assignment, then add or update a regression test so this message is no longer reported as a hardcoded password.