cleanup fit_bounds.js template (#1920)

Author: Conengmo

folium/templates/fit_bounds.js

@@ -12,7 +12,7 @@
 import pandas as pd
 import pytest
 import xyzservices.providers as xyz
-from jinja2 import Environment, PackageLoader
+from jinja2 import Template
 from jinja2.utils import htmlsafe_json_dumps
 
 import folium
@@ -69,7 +69,21 @@ def setup_method(self):
             font_size="1.5rem",
             attr=attr,
         )
-        self.env = Environment(loader=PackageLoader("folium", "templates"))
+        self.fit_bounds_template = Template(
+            """
+            {% if autobounds %}
+            var autobounds = L.featureGroup({{ features }}).getBounds()
+            {% if not bounds %}
+            {% set bounds = "autobounds" %}
+            {% endif %}
+            {% endif %}
+            {% if bounds %}
+            {{this._parent.get_name()}}.fitBounds({{ bounds }},
+                {{ fit_bounds_options }}
+            );
+            {% endif %}
+        """
+        )
 
     def test_init(self):
         """Test map initialization."""
@@ -385,8 +399,7 @@ def test_fit_bounds(self):
         ][0]
         out = self.m._parent.render()
 
-        fit_bounds_tpl = self.env.get_template("fit_bounds.js")
-        fit_bounds_rendered = fit_bounds_tpl.render(
+        fit_bounds_rendered = self.fit_bounds_template.render(
             {
                 "bounds": json.dumps(bounds),
                 "this": fitbounds,
@@ -406,8 +419,7 @@ def test_fit_bounds_2(self):
         ][0]
         out = self.m._parent.render()
 
-        fit_bounds_tpl = self.env.get_template("fit_bounds.js")
-        fit_bounds_rendered = fit_bounds_tpl.render(
+        fit_bounds_rendered = self.fit_bounds_template.render(
             {
                 "bounds": json.dumps(bounds),
                 "fit_bounds_options": json.dumps(