Remove importlib-metadata dependency (streamlit#8094)

## Describe your changes

The `importlib-metadata` is a backport to bring some of the
`importlib.metadata` functionality to pre Python 3.7. But we don't
support Python 3.7 anymore, so we can just remove this dependency.

---

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project are made under the Apache 2.0 license.

lib/min-constraints-gen.txt

@@ -3,7 +3,6 @@ blinker==1.0.0
 cachetools==4.0
 click==7.0
 gitpython==3.0.7
-importlib-metadata==1.4
 numpy==1.19.3
 packaging==16.8
 pandas==1.3.0

lib/setup.py

@@ -33,8 +33,6 @@
     "blinker>=1.0.0, <2",
     "cachetools>=4.0, <6",
     "click>=7.0, <9",
-    # 1.4 introduced the functionality found in python 3.8's importlib.metadata module
-    "importlib-metadata>=1.4, <8",
     "numpy>=1.19.3, <2",
     "packaging>=16.8, <24",
     # Lowest version with available wheel for 3.7 + amd64 + linux

lib/streamlit/version.py

@@ -14,9 +14,9 @@
 
 """Streamlit version utilities."""
 import random
+from importlib.metadata import version as _version
 
 import packaging.version
-from importlib_metadata import version as _version
 from typing_extensions import Final
 
 import streamlit.logger as logger