slither-read-storage `--table` prints variables from imported contracts with incorrect values

### Describe the issue:

In addition to printing the variables in the Unitroller's storage layout, `slither-read-storage 0x3d9819210a31b4961b30ef54be2aed79b9c9cd3b --value --table --rpc-url ` is printing variables it found in other imported contracts, some of which do not belong in the Unitroller's storage.

Specifically, it is including variables from `ComptrollerV1Storage`, which technically are stored in the Unitroller's storage. So the values are correct, though the variables are not directly inherited by the Unitroller contract. It is also including variables declared in `CToken`, which is a completely separate contract with its own storage. As a result, the tool is reporting incorrect values for these variables, since it is reading from the Untroller's storage and not the CToken's.

### Code example to reproduce the issue:

https://etherscan.io/address/0x3d9819210a31b4961b30ef54be2aed79b9c9cd3b#code

`slither-read-storage 0x3d9819210a31b4961b30ef54be2aed79b9c9cd3b --value --table --rpc-url `

### Version:

0.9.2 (current dev branch)

### Relevant log output:

```shell
+----------------------------------+-------------------------------------------------+------+------+--------+---------------------------------------------------+
| name | type_string | slot | size | offset | value |
+----------------------------------+-------------------------------------------------+------+------+--------+---------------------------------------------------+
| accountAssets | mapping(address => CToken[]) | 8 | 256 | 0 | 0 |
| maxAssets | uint256 | 7 | 256 | 0 | 20 |
| liquidationIncentiveMantissa | uint256 | 6 | 256 | 0 | 1080000000000000000 |
| closeFactorMantissa | uint256 | 5 | 256 | 0 | 500000000000000000 |
| oracle | PriceOracle | 4 | 160 | 0 | 50ce56a3239671ab62f185704caedf626352741e |
| pendingComptrollerImplementation | address | 3 | 160 | 0 | 0x0000000000000000000000000000000000000000 |
| comptrollerImplementation | address | 2 | 160 | 0 | 0xBafE01ff935C7305907c33BF824352eE5979B526 |
| accountBorrows | mapping(address => CToken.BorrowSnapshot) | 17 | 256 | 0 | 0 |
| transferAllowances | mapping(address => mapping(address => uint256)) | 16 | 256 | 0 | 0 |
| accountTokens | mapping(address => uint256) | 15 | 256 | 0 | 0 |
| totalSupply | uint256 | 14 | 256 | 0 | 176000000000000000 |
| totalReserves | uint256 | 13 | 256 | 0 | 20 |
| totalBorrows | uint256 | 12 | 256 | 0 | 0 |
| borrowIndex | uint256 | 11 | 256 | 0 | 0 |
| accrualBlockNumber | uint256 | 10 | 256 | 0 | 1073021371786102711066046704037845102107483570476 |
| reserveFactorMantissa | uint256 | 9 | 256 | 0 | 0 |
| initialExchangeRateMantissa | uint256 | 8 | 256 | 0 | 0 |
| interestRateModel | InterestRateModel | 7 | 160 | 0 | 0000000000000000000000000000000000000014 |
| comptroller | ComptrollerInterface | 6 | 160 | 0 | 0000000000000000000000000efcee47256c0000 |
| pendingAdmin | address | 1 | 160 | 0 | 0x0000000000000000000000000000000000000000 |
| admin | address | 0 | 160 | 0 | 0x6d903f6003cca6255D85CcA4D3B5E5146dC33925 |
| decimals | uint256 | 3 | 256 | 0 | 0 |
| symbol | string | 2 | 256 | 0 | 1067536846733826965994198726057517433926444496166 |
| name | string | 1 | 256 | 0 | |
| _guardCounter | uint256 | 0 | 256 | 0 | 625496822074558125566300987011552446920364603685 |
+----------------------------------+-------------------------------------------------+------+------+--------+---------------------------------------------------+
```