Importing FBX creates new materials when using the search materials import setting

There is an issue when importing FBX that creates new materials when using the search materials import setting. Instead of being able to use the material that is in the Base Material name, the texture and material imports anyway. This issue only occurs if the material being imported contains a texture. This issue is a regression.

Versions Tested:
4.16.3 - CL: 3561208 - Issue does not occur
4.17.2 - CL: 3658906 - Issue occurs
4.18.0 - CL: 3709383 - Issue occurs

1. Create a new project (no template or starter content needed)
2. Create two folders in the content browser
3. Using the FBX file provided import the FBX into the first folder
4. Use the default import settings and use the import all button
5. Using the FBX file provided import the FBX into the second folder
6. In the import settings under the Material > Change the Search Location to "All Assets"
7. Change the Base Material Name to "Lambert 1" > attempt to change the properties
8. Click the import button
   Result: The FBX imports with a new copy of the texture and Material
   Expected Result: Only the FBX imports with no duplicate texture or material