fix: resolve curl_cffi TLS errors and fix FRED/upgrades endpoints

- Pin curl_cffi==0.7.4 to avoid BoringSSL bug in 0.12-0.14
- Patch curl_cffi Session to use safari TLS fingerprint instead of
  chrome, which triggers SSL_ERROR_SYSCALL on some networks
- Register FRED API key with OpenBB credentials at startup
- Fix macro overview to return latest data instead of oldest, and
  extract values by FRED series ID key
- Replace Finnhub upgrades endpoint (premium-only) with yfinance
  upgrades_downgrades which includes price target changes
- Remove redundant curl_cffi upgrade from Dockerfile

Dockerfile

@@ -12,7 +12,6 @@ COPY pyproject.toml ./
 
 RUN pip install --no-cache-dir . && \
     pip install --no-cache-dir openbb-quantitative openbb-econometrics openbb-technical && \
-    pip install --no-cache-dir --upgrade curl_cffi && \
     apt-get purge -y gcc g++ libssl-dev && \
     apt-get autoremove -y