Images not being logged after using auto_lr_find
🐛 Bug
When I use the auto LR finder, the images that I logged are no longer being displayed in Tensorboard. The logging works normally when setting it to False or when not specifying it.
To Reproduce
Steps to reproduce the behavior:

Set  auto_lr_find = True for the trainer
Log image during test/validation step as self.logger.experiment.add_image(title, image, step)
Load the Tensorboard WebUI and see that the image is not being logged

Expected behavior
The image that I logged should be visible in Tensorboard, even when using auto LR finder.
Environment
* CUDA:
        - GPU:
                - GeForce GTX 1050 Ti with Max-Q Design
        - available:         True
        - version:           10.2
* Packages:
        - numpy:             1.18.3
        - pyTorch_debug:     False
        - pyTorch_version:   1.5.0
        - pytorch-lightning: 0.7.6
        - tensorboard:       2.2.1
        - tqdm:              4.46.0
* System:
        - OS:                Linux
        - architecture:
                - 64bit
                - ELF
        - processor:         x86_64
        - python:            3.8.2
        - version:           #41~1586790036~18.04~600aeb5-Ubuntu SMP Mon Apr 13 17:47:15 UTC


How you installed PyTorch (conda, pip, source): pip

Additional context
Not sure if relevant, but I couldn't figure out how to pass the params to the Trainer as I'm using from_argparse_args(hparams), where hparams contains the keys and values obtained from command-line ArgumentParser. So I set hparams.auto_lr_finder = True before instantiating the Trainer. The LR finder work's, so I assume there's no issue with that.