Memory footprint excessive

#### Environment details

- OS type and version: MacOS 15.1.1 (24B91)
- Python version: Python 3.12.0
- pip version: pip 24.3.1
- `google-cloud-aiplatform` version: Version: 1.72.0

#### Steps to reproduce
Get the memory footprint of python doing a simple and similar import. An unladen swallow is about 10MiB:

```
/usr/bin/time -l python -c 'import google.cloud'
0.03 real 0.01 user 0.00 sys
10878976 maximum resident set size <-- 11Mi
0 average shared memory size
0 average unshared data size
0 average unshared stack size
906 page reclaims
14 page faults
0 swaps
0 block input operations
0 block output operations
0 messages sent
0 messages received
0 signals received
24 voluntary context switches
29 involuntary context switches
134544684 instructions retired
52246608 cycles elapsed
7226432 peak memory footprint <-- 6.9Mi
```

Get memory footprint when importing aiplatform. It uses around 180MiB just doing the basic import.

```
/usr/bin/time -l python -c 'import google.cloud.aiplatform'
1.36 real 0.95 user 0.15 sys
191102976 maximum resident set size <-- 183Mi
0 average shared memory size
0 average unshared data size
0 average unshared stack size
20349 page reclaims
381 page faults
0 swaps
0 block input operations
0 block output operations
0 messages sent
0 messages received
0 signals received
2297 voluntary context switches
376 involuntary context switches
8019160261 instructions retired
3445365715 cycles elapsed
178669120 peak memory footprint <-- 171Mi
```

Start by reproducing the two /usr/bin/time commands from the issue in the stated Python and google-cloud-aiplatform versions, then profile the import path for google.cloud.aiplatform. The issue does not name files or tests; done would require identifying the source of the excess import-time memory and demonstrating a reduced footprint with a regression check.

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