Ensure log() calls from jinja ensure the msg is stringified

The simplest way to resolve [CT-2259](#7108)
and [CT-1783](#6568) in backports
to dbt-core < 1.4 is to ensure `msg` in `BaseContext.log()` is stringified.

core/dbt/context/base.py

@@ -456,6 +456,10 @@ def log(msg: str, info: bool = False) -> str:
               {{ log("Running some_macro: " ~ arg1 ~ ", " ~ arg2) }}
             {% endmacro %}"
         """
+
+        if not isinstance(msg, str):
+            msg = str(msg)
+
         if info:
             fire_event(MacroEventInfo(msg))
         else: