Alt text is not descriptive [geo pages]

**Describe the content issue**:
Images listed below do not have descriptive/informative alt text. For markdown the alt text is located between the square brackets, ``.

The list below isn't exhaustive since I found these images based on the word count for the alt text, but it should be a good starting point to make our alt text better for people who use screen readers.

Some resources to help write alt text:
- https://webaim.org/techniques/alttext/
- https://www.a11yproject.com/posts/are-you-making-these-five-mistakes-when-writing-alt-text/

https://github.com/aws-amplify/docs/blob/main/src/pages/[platform]/build-a-backend/more-features/geo/configure-geofencing/index.mdx:
```
194
195: Then click on the Add users button that displays a window to select the users by their username, email etc. that you intend to add to the Cognito group. Note: the user(s) added to the Cognito User Pool Group may need to be re-authenticated by signing out and signing in again. 
196
```

 

https://github.com/aws-amplify/docs/blob/main/src/pages/[platform]/prev/build-a-backend/more-features/geo/configure-geofencing/index.mdx:
```
220
221: Then click on the Add users button that displays a window to select the users by their username, email etc. that you intend to add to the Cognito group. Note: the user(s) added to the Cognito User Pool Group may need to be re-authenticated by signing out and signing in again. 
222
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib/geo/ios/search/30_location_search_map.mdx:
```
49
50: 
51

75
76: 
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib/geo/js/geofences.mdx:
```
130
131: 
132
133: 
134
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib/geo/js/google-migration.mdx:
```
173
174: 
175

295
296: 
297

353
354: 
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib/geo/js/maps.mdx:
```
94
95: 
96

148
149: 
150
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib/geo/js/search.mdx:
```
69
70: 
71

87
88: 
89
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib-v1/geo/ios/search/30_location_search_map.mdx:
```
46
47: 
48

72
73: 
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib-v1/geo/js/geofences.mdx:
```
131
132: 
133
134: 
135
```

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib-v1/geo/js/google-migration.mdx:
```
173
174: 
175

295
296: 
297

353
354: 
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib-v1/geo/js/maps.mdx:
```
94
95: 
96

148
149: 
150
```

 

https://github.com/aws-amplify/docs/blob/main/src/fragments/lib-v1/geo/js/search.mdx:
```
69
70: 
71

89
90: 
91
```